本研究的主要目的是探索二維（2D）材料的光電特性，並製作成高性能元件。論文內容由四個項目組成，這些項目包含通過摻雜、基板修飾以及與其他2D材料組裝以獲得高性能光致電晶體管的異質結構來調節InSe的光電性能。首先，利用剝落的In1-xSnxSe奈米薄片（透過在InSe中摻雜Sn獲得）以製造光致電晶體的元件和特性， In1-xSnxSe內部增強的電性可表現出2560±240 cm2V-1s-1的超高遷移率，作為光致電晶體，它對光的吸收非常敏感。其次，通過在光激發下施加系統的機械應變，證明了In1-xSnxSe彈性元件中的壓電性能，有趣的是，我們發現在2.7％ 的彎曲應變下，暗電流和光電流增加了五倍。第三，我們展示了一種替代方法，可通過使用薄介電間隔物（h-BN）來增強帶第II型能帶（InSe/GeS）凡得瓦異質結中的電荷分離並改變物理性質，透過光學和電學的測量結果證實了上述的理論，並且通過h-BN介電增強的電荷分離表現出9×10^2 A W-1和3.4×10^14 Jones的光響應性和檢測率。最後，我們在 和彈性PET基板上證明了第II型能帶排列的n-InSe/p-WSe2異質結構中的反雙極轉移行為。利用在彈性PET基板上的頂層匣控反雙極型光致電晶體上施加外部拉伸應變，我們觀察到元件中兩個導通狀態會產生雙反雙極性晶體，由光致發光研究和電性測量證實是起因於載流子傳輸路徑的改變。我們的研究證明InSe/WSe2異質結構中的可調變光電特性對於未來應用在彈性反雙極性電晶體有極大的發展性。

The main objective of my research is to explore the optoelectronic property of two-dimensional (2D) materials and implement them to obtain high-performance devices. This thesis consists of four projects which involve modulating the optoelectronic property of InSe through doping, substrate modification, and assembling with other 2D materials to obtain heterostructures for high-performance phototransistors. Firstly, the device fabrication and characterization of exfoliated In1-xSnxSe nanoflakes (obtained by doping Sn in InSe) to make a phototransistor have been reported. The internally boosted electrical properties of In1-xSnxSe exhibit ultra-high mobility of 2560 ± 240 cm2V-1s-1 and as a phototransistor, it is highly sensitive with large optical absorption. Secondly, the piezophototronic properties in In1−xSnxSe flexible devices have been demonstrated by applying systematic mechanical strain under photoexcitation. Interestingly, we discover that the dark current and photocurrent are increased by five times under a bending strain of 2.7%. Thirdly, we demonstrate an alternative approach to enhance charge separation and alter physical properties in van der Waals heterojunctions with type-II band alignment (InSe/GeS) by using thin dielectric spacers (h-BN). The optical and electrical measurements support the above statement and the enhanced charge separation with h-BN mediation manifests a photoresponsivity and detectivity of 9 × 102 A W−1 and 3.4 × 1014 Jones. At last, we demonstrate the anti-ambipolar transfer behavior in type-II band aligned n-InSe/p-WSe2 heterostructure on a flexible polyethylene terephthalate (PET) substrate. By applying external mechanical strain to the top-gated anti-ambipolar transistor, we observe two ON states in the device giving rise to bi-anti-ambipolar transistor. It is due to the modification of the carrier transport paths as confirmed with the photoluminescence and electrical measurement study. Therefore, our study which demonstrates the strain-tunable optoelectronic property in InSe/WSe2 heterostructure will be useful for the development of flexible anti-ambipolar phototransistors in near future.

Contents
Abstract…………………………………………………………………………i
Acknowledgements……………………………………………………………iii
Contents………………………………………………………………………...v
List of Figures…………………………………………………………………..x
List of Tables………………………………………………………………..xxiv
List of Abbreviations………………………………………………………..xxv

Chapter 1: Introduction……………………………………………………….1
1.1 Two-dimensional Materials……………………………………………………………1
1.2 Transition Metal Dichalcogenides……………………………………………………..2
1.3 Indium Selenide………………………………………………………………………..3
1.4 Germanium Sulfide…………………………………………………………………….5
1.5 Hexagonal Boron Nitride………………………………………………………………6
1.6 Tungsten Diselenide…………………………………………………………………...8
1.7 Objective of the research……………………………………………………………….9

Chapter 2: Fabrication and Characterization Techniques………………...13
2.1 Mechanical Exfoliation Technique…………………………………………………...13
2.2 Van der Waals Heterostructures……………………………………………………...15
2.3 Electrode Deposition…………………………………………………………………17
2.4 X-ray Diffraction……………………………………………………………………..19
2.5 Atomic Force Microscopy……………………………………………………………20
2.6 Scanning Electron Microscopy……………………………………………………….22
2.7 Transmission Electron Microscopy…………………………………………………..24
2.8 Photoluminescence Spectroscopy…………………………………………………….26
2.9 Raman Spectroscopy………………………………………………………………....27
2.10 X-ray Photoelectron Spectroscopy………………………………………………….29
2.11 Electrical Measurements……………………………………………………………30

Chapter 3: High Mobility In1-xSnxSe Phototransistor………………………32
3.1 Introduction…………………………………..............................................................32
3.2 Experimental Details…………………………………………………………………34
3.2.1 InSnSe Crystal Growth………………………………………………………...34
3.2.2 Device Fabrication……………………………………………………………..34
3.2.3 Theoretical Method…………………………………………………………….35
3.2.4 Characterization Methods……………………………………………………...35
3.3 Results and Discussion………………………………………………………………..36
3.3.1 Material Characterization………………………………………...…………….36
3.3.2 Transfer Characteristics on Different Substrates……………………………….40
3.3.3 Photoluminescence and Raman Spectroscopy………………………………….46
3.3.4 X-ray Photoelectron Spectroscopy……………………………………………..49
3.3.5 First-principles Density Functional Calculations………………………………51
3.3.6 InSnSe Phototransistor…………………………………………………………56
3.3.7 Photodetecting Properties of the InSnSe Device………………………………..58
3.4 Summary……………………………………………………………………………...67
Chapter 4: Flexible Piezopotential Gated In1-xSnxSe Phototransistor……...68
4.1 Introduction………………………………………………………………………….. 68
4.2 Experimental Details………………………………………………………………… 70
4.2.1 Synthesis of InSnSe Crystals…………………………………………………...70
4.2.2 Device Fabrication…………………………….………………………………. 71
4.2.3 Characterization Methods……………………………………………………... 71
4.3 Results and Discusssion………………………………………………………………72
4.3.1 Material Characterization………………………………………………………72
4.3.2 Electrical Measurements without Strain………………………………………..73
4.3.3 Electrical Measurements with Strain…………………………………………...77
4.3.4 Energy Band Diagram………………………………………………………….83
4.3.5 Photoluminescence Spectroscopy……………………………………………... 86
4.3.6 Raman Spectroscopy…………………………………………………………...88
4.3.7 Wearable Photodetector……………………………………………………….. 94
4.4 Summary…………………………………………………………………………….. 97

Chapter 5: Modulating Charge Separation with h-BN Mediation in Vertical van der Waals Heterostructures……………………………………………..98
5.1 Introduction………………………………………………………………………….. 98
5.2 Experimental Details……………………………………………………………….. 101
5.2.1 Crystal Growth…………………………………………………......................101
5.2.2 Device Fabrication…………………………….……………………………...101
5.2.3 Characterization Details……………………………………………………....102
5.3 Results and Discusssion……………………………………………………………..103
5.3.1 Material Characterization……………………………………………………..103
5.3.2 Optical Studies……………………………………………………………….. 106
5.3.2.1 Photoluminescence Spectrum…………………………………………107
5.3.2.2 Ultrafast Pump-probe Measurements…………………………………110
5.3.2.3 Raman Spectrum………………………………………………………115
5.3.3 Electrical Measurements…………………………………………................... 117
5.3.3.1 InSe/GeS Heterostructure……………………………………………..117
5.3.3.2 InSe/h-BN/GeS Heterostructure………………………………………122
5.3.4 Carrier Transport Mechanism…………………………………………………129
5.4 Summary…………………………………………………………………………… 132

Chapter 6: Strain Tunable Bi-anti-ambipolar Transistor…………….......134
6.1 Introduction…………………………………............................................................ 134
6.2 Experimental Details……………………………………………………………….. 136
6.2.1 Crystal Growth………………………………………………………..............136
6.2.2 Device Fabrication……………………………………………………………137
6.2.3 Characterization Details……………………………………………………....137
6.3 Results and Discussion………………………………………………………………138
6.3.1 Device Structure………………………………………...…………………….138
6.3.2 Transfer Characteristics……………………………………………………….142
6.3.3 Strain Tunable Transfer Characteristics…...………………………………….144
6.3.4 Photoluminescence Spectrum………………………………………………... 149
6.3.5 Photoresponse Study………………………….………………………………152
6.4 Summary…………………………………………………………………………….160

Chapter 7: Conclusion and Prospective………………….............................161
References………………………………..…………………..........................164
Appendix A: Publications……………….…………………..........................188
Appendix B: International Conferences.….…………………......................191
Appendix C: Recognitions……………….………………….........................192

References
[1] K. S. Novoselov, A. Mishchenko, A. Carvalho and A. H. Castro Neto, 2D materials and van der Waals heterostructures, Science, 2016, 353, aac9439.
[2] M. Zeng, Y. Xiao, J. Liu, K. Yang and L. Fu, Exploring Two-Dimensional Materials toward the Next-Generation Circuits: From Monomer Design to Assembly Control, Chem. Rev. 2018, 118, 6236−6296.
[3] W. Choi, N. Choudhary, G. H. Han, J. Park, D. Akinwande and Y. H. Lee, Recent development of two-dimensional transition metal dichalcogenides and their applications, Mater. Today, 2017, 20, 116-130.
[4] M. Chhowalla, D. Jena, and H. Zhang, Two-dimensional semiconductors for transistors, Nat. Rev. Maters, 2016, 1, 16052.
[5] A. K. Geim and I. V. Grigorieva, Van der Waals heterostructures, Nature, 2013, 499, 419-425.
[6] D. Akinwande, N. Petrone, and J. Hone, Two-dimensional flexible nanoelectronics, Nat. Commun, 2014, 5, 5678.
[7] J. H. Kim, J. H. Jeong, N. Kim, R. Joshi and G. H. Lee, Mechanical properties of two-dimensional materials and their applications, J. Phys. D: Appl. Phys., 2019, 52, 083001.
[8] G. S. Duesberg, Heterojunctions in 2D semiconductors: A perfect match, Nat. Mater, 2014, 13, 1075-1076.
[9] H. Zenga and X. Cui, An optical spectroscopic study on two-dimensional group-VI transition metal dichalcogenides, Chem. Soc. Rev., 2015, 44, 2629.
[10] Ruitao Lv, J. A. Robinson, R. E. Schaak, D. Sun, Y. Sun, T. E. Mallouk, and M. Terrones, Transition metal dichalcogenides and beyond: synthesis, properties, and applications of single- and few-layer nanosheets, Acc. Chem. Res. 2015, 48, 56-64.
[11] Q. H. Wang, K. Kalantar Zadeh, A. Kis, J. N. Coleman and M. S. Strano, Electronics and optoelectronics of two-dimensional transition metal dichalcogenides, Nat. Nanotechnol., 2012, 7, 699–712.
[12] J.A. Reyes-Retana and F. Cervantes-Sodi, Spin-orbital effects in metal-dichalcogenide semiconducting monolayers, Sci. Reports, 2016, 6, 24093.
[13] T. Cao, G. Wang, W. Han, H. Ye, C. Zhu, J. Shi, Q. Niu, P. Tan, E. Wang, B. Liu and J. Feng, Valley-selective circular dichroism of monolayer molybdenum disulphide, Nat. Commun, 2012, 3, 887.
[14] D. Jariwala, V. K. Sangwan, L. J. Lauhon, T. J. Marks, and M. C. Hersam, Emerging Device Applications for Semiconducting Two-Dimensional Transition Metal Dichalcogenides, ACS Nano, 2014, 8, 1102-1120.
[15] A. Politano, D. Campi, M. Cattelan, I. Ben Amara, S. Jaziri, A. Mazzotti, A. Barinov, B. Gürbulak, S. Duman, S. Agnoli, L. S. Caputi, G. Granozzi and A. Cupolillo, Indium selenide: an insight into electronic band structure and surface excitations, Sci. Reports, 2017, 7, 3445.
[16] G.W. Mudd, M. R. Molas, X. Chen, V. Zólyomi, K. Nogajewski, Z. R. Kudrynskyi, Z. D. Kovalyuk, G.Yusa, O. Makarovsky, L. Eaves, M. Potemski, V. I. Falko and A. Patanè, The direct-to-indirect band gap crossover in two-dimensional van der Waals Indium Selenide crystals, Sci. Reports, 2016, 6, 39619.
[17] G. W. Mudd, S. A. Svatek, T. Ren, A. Patanè, O. Makarovsky, L. Eaves, P. H. Beton, Z. D. Kovalyuk, G. V. Lashkarev, Z. R. Kudrynskyi and A. I. Dmitriev, Tuning the bandgap of exfoliated InSe nanosheets by quantum confinement, Adv. Mater. 2013, 25, 5714–5718.
[18] D. W. Boukhvalov, B. Gürbulak, S. Duman, L. Wang, A. Politano, L. S. Caputi, G. Chiarello and A. Cupolillo, The Advent of Indium Selenide: Synthesis, Electronic Properties, Ambient Stability and Applications, Nanomaterials, 2017, 7, 372.
[19] E. Sutter, B. Zhang, M. Sun, P. Sutter, Few-Layer to Multilayer Germanium (II) Sulfide: Synthesis, Structure, Stability, and Optoelectronics, ACS Nano, 2019, 13, 9352-9362.
[20] R. K. Ulaganathan, Y.-Y Lu, C.-J. Kuo, S. R. Tamalampudi, R. Sankar, K. M. Boopathi, A. Anand, K. Yadav, R. J. Mathew, C.-R Liu, F. C. Chou, Y.-T. Chen, High photosensitivity and broad spectral response of multi-layered germanium sulfide transistors, Nanoscale, 2016, 8, 2284-2292.
[21] P. Ramasamy, D. Kwak, D.-H. Lim, H.-S. Ra, J.-S. Lee, Solution synthesis of GeS and GeSe nanosheets for high-sensitivity photodetectors, J. Mater. Chem. C, 2016, 4, 479-485.
[22] M. Topsakal, E. Akturk, S. Ciraci, First-principles study of two- and one-dimensional honeycomb structures of boron nitride, Phys. Rev. B: Condens. Matter Mater. Phys., 2009, 79, 11544201-11544211.
[23] R. Gao, L. Yin, C. Wang, Y. Qi, N. Lun, L. Zhang, Y. X. Liu, L. Kang and X. Wang, High-Yield Synthesis of Boron Nitride Nanosheets with Strong Ultraviolet Cathodoluminescence Emission, J. Phys. Chem. C, 2009, 113, 15160–15165.
[24] R. V. Gorbachev, I. Riaz, R. R. Nair, R. Jalil, L. Britnell, B. D. Belle, E. W. Hill, K. S. Novoselov, K. Watanabe, T. Taniguchi, Hunting for Monolayer Boron Nitride: Optical and Raman Signatures, Small, 2011, 7, 465-458.
[25] A. S. Mayorov, R. V. Gorbachev,S. V. Morozov, L. Britnell, R. Jalil, L. A. Ponomarenko, P. Blake, K. S. Novoselov, K. Watanabe, T. Taniguchi, A. K. Geim, Micrometer-Scale Ballistic Transport in Encapsulated Graphene at Room Temperature, Nano Lett., 2011, 11, 2396–2399.
[26] X. Su, R. Zhang, C. Guo, M. Guo, Z. Ren, Quantum wells formed in transition-metal dichalcogenide nanosheet-superlattices: stability and electronic structures from first principles, Phys.Chem.Chem.Phys., 2014, 16, 1393-1398.
[27] W. Zhao, R. M. Ribeiro, M. Toh, A. Carvalho, C. Kloc, A. H. Castro Neto, G. Eda, Origin of Indirect Optical Transitions in Few-Layer MoS2, WS2, and WSe2, Nano Lett., 2013, 13, 5627−5634.
[28] J.-H. Lee, J. Y. Park, E. B. Cho, T. Y. Kim, S. A. Han, T.-H. Kim, Y. Liu, S. K. Kim, C. J. Roh, H.-J. Yoon, H. Ryu, W. Seung, J. S. Lee, J. Lee, S.-W. Kim, Reliable Piezoelectricity in Bilayer WSe2 for Piezoelectric Nanogenerators, Adv. Mater., 2017, 29, 16067.
[29] M. Yi and Z. Shen, A review on mechanical exfoliation for the scalable production of graphene, J. Mater. Chem. A, 2015, 3, 11700-11715.
[30] Y. Liu, N. O. Weiss, X. Duan, H.-C. Cheng, Y. Huang and X. Duan, Van der Waals heterostructures and devices, Nat Rev Mater., 2016, 1, 16042.
[31] R. J. Martin-Palma and A. Lakhtakia, Chapter 15 - Vapor-Deposition Techniques, Engineered Biomimicry, Elsevier, 2013, 383-398.
[32] Y. Shan and Hongda Wang, The structure and function of cell membranes examined by atomic force microscopy and single-molecule force spectroscopy, Chem. Soc. Rev., 2015, 44, 3617-3638.
[33] R. Asmatulu and W. S. Khan, Chapter 13 - Characterization of electrospun nanofibers, Synthesis and Applications of Electrospun Nanofibers, Micro and Nano Technologies, Elsevier, 2019, 257-281.
[34] N. Marturi. Vision and visual servoing for nanomanipulation and nanocharacterization in scanning electron microscope. Micro and nanotechnologies/Microelectronics. Universite de Franche-Comte, 2013.
[35] M. J. Baker, C. S. Hughes and K. A. Hollywood, Chapter 3-Raman spectroscopy, Biophotonics: Vibrational Spectroscopic Diagnostics, IOP Concise Physics, 2016, 1-13.
[36] D. R. Baer and S. Thevuthasan, Chapter 16 - Characterization of Thin Films and Coatings, Handbook of Deposition Technologies for Films and Coatings, Elsevier, 2009, 749-864.
[37] S. Bae, H. Kim, Y. Lee,X. Xu, J. S. Park, Y. Zheng, J. Balakrishnan, T. Lei, H. Ri Kim, Y. I. Song, Y.-J. Kim, K. S. Kim, B. Ozyilmaz, J.-H. Ahn, B. H. Hong, S. Iijima. Roll-to-roll production of 30-inch graphene films for transparent electrodes, Nat. Nanotechnol., 2010, 5, 574–578.
[38] K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, M. I. Katsnelson, I. V. Grigorieva, S. V. Dubonos, A. Firsov, Two-dimensional gas of massless Dirac fermions in graphene, Nature, 2005, 438, 197–200.
[39] M. Buscema, J. O. Island, D. J. Groenendijk, S. I. Blanter, G. A. Steele, G. A.; H. S. J. Van Der Zant, A. Castellanos-Gomez, Photocurrent generation with two-dimensional van der Waals semiconductors, Chem. Soc. Rev., 2015, 44, 3691–3718.
[40] C. Xie, C. Mak, X. Tao, F. Yan, Photodetectors Based on Two-Dimensional Layered Materials Beyond Graphene, Adv. Funct. Mater. 2017, 27, 1603886.
[41] O. Lopez-Sanchez, D. Lembke, M. Kayci, A. Radenovic, A. Kis, Ultrasensitive photodetectors based on monolayer MoS2, Nat. Nanotechnol., 2013, 8, 497-501.
[42] M. W. Iqbal, M. Z. Iqbal, M. F. Khan, M. A. Shehzad, Y. Seo, J. H. Park, C. Hwang, J. Eom, High-mobility and air-stable single-layer WS2 field-effect transistors sandwiched between chemical vapor deposition-grown hexagonal BN films, Sci. Rep. 2015, 5, 10699.
[43] D. A. Nguyen, H. M. Oh, N. T. Duong, S. Bang, S. J. Yoon, M. S. Jeong, Highly Enhanced Photoresponsivity of a Monolayer WSe2 Photodetector with Nitrogen-Doped Graphene Quantum Dots, ACS Appl. Mater. Interfaces 2018, 10, 10322–10329.
[44] B. Radisavljevic, A. Radenovic, J. Brivio, V. Giacometti, A. Kis, Single-layer MoS2 transistors, Nat. Nanotechnol. 2011, 6, 147–150.
[45] S. Kim, A. Konar, W. S. Hwang, J. H. Lee, J. Lee, J. Yang, C. Jung, H. Kim, J. B. Yoo, J. Y. Choi, Y. W. Jin, S. Y. Lee, D. Jena, W. Choi and K. Kim, High-mobility and low-power thin-film transistors based on multilayer MoS2 crystals, Nat. Commun., 2012, 3, 1011–1017.
[46] Y. Zhang, J. Ye, Y. Matsuhashi, Y. Iwasa, Ambipolar MoS2 Thin Flake Transistors, Nano Lett., 2012, 12, 1136–1140.
[47] W. Bao, X. Cai, D. Kim, K. Sridhara, M. S. Fuhrer, High mobility ambipolar MoS2 field-effect transistors: Substrate and dielectric effects, Appl. Phys. Lett., 2013, 102, 042104.
[48] J. H. Kim, T. H. Kim, H. Lee, Y. R. Park, W. Choi, C. J. Lee, Thickness-dependent electron mobility of single and few-layer MoS2 thin-film transistors, AIP Adv, 2016, 6, 065106.
[49] S. Das, H. Y. Chen, A. V. Penumatcha, J. Appenzeller, High performance multilayer MoS2 transistors with scandium contacts, Nano Lett., 2013, 13, 100–105.
[50] L. Li, Y. Yu, G. J. Ye, Q. Ge, X. Ou, H. Wu, D. Feng, X. H. Chen, Y. Zhang, Black phosphorus field-effect transistors, Nat. Nanotechnol. 2014, 9, 372–377.
[51] E. Kress-Rogers, R. J. Nicholas, J. C. Portal, A. Chevy, Cyclotron resonance studies on bulk and two-dimensional conduction electrons in InSe, Solid State Commun. 1982, 44, 379–383.
[52] S. R. Tamalampudi, Y. Y. Lu, U. R. Kumar, R. Sankar, C. Da Liao, B. K. Moorthy, C. H. Cheng, F. C. Chou, Y. T. Chen, High performance and bendable few-layered InSe photodetectors with broad spectral response, Nano Lett., 2014, 14, 2800-2806.
[53] W. Feng, W. Zheng, W. Cao, P. Hu, Back gated multilayer InSe transistors with enhanced carrier mobilities via the suppression of carrier scattering from a dielectric interface, Adv. Mater. 2014, 26, 6587–6593.
[54] S. Sucharitakul, N. J. Goble, R. U. Kumar, R. Sankar, Z. A. Bogorad, F. C. Chou, Y. T. Chen, X. P. Gao, Intrinsic Electron Mobility Exceeding 103 cm2/(V s) in Multilayer InSe FETs, Nano Lett. 2015, 15, 3815–3819.
[55] P. H. Ho, Y. R. Chang, Y. C. Chu, M. K. Li, C. A. Tsai, W. H. Wang, C. H. Ho, C. W. Chen, P. W. Chiu, High-Mobility InSe Transistors: The Role of Surface Oxides, ACS Nano 2017, 11, 7362–7370.
[56] X. Hou, S. Chen, Z. Du and J. Cui, Improvement of the thermoelectric performance of InSe-based alloys doped with Sn, RSC Adv., 2015, 5, 102856-102862.
[57] S. Lei, L. Ge, S. Najmaei, A. George, R. Kappera, J. Lou, M.Chhowalla, H. Yamaguchi, G. Gupta, R. Vajtai, A. D. Mohite and P. M. Ajayan, Evolution of the electronic band structure and efficient photo-detection in atomic layers of InSe, ACS Nano, 2014, 8, 1263-1272.
[58] W. Feng, J. B. Wu, X. Li, W. Zheng, X. Zhou, K. Xiao, W. Cao, B. Yang, J. C. Idrobo, L. Basile, W. Tian, P. H. Tan and P. A. Hu, Ultrahigh photo-responsivity and detectivity in multilayer InSe nanosheets phototransistors with broadband response, J. Mater. Chem. C 2015, 3, 7022–7028.
[59] W. Luo, Y. Cao, P. Hu, K. Cai, Q. Feng, F. Yan, T. Yan, X. Zhang, K. Wang, Gate Tuning of High-Performance InSe-Based Photodetectors Using Graphene Electrodes, Adv. Opt. Mater. 2015, 3, 1418–1423.
[60] G. Kresse and J. Furthmuller, Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set, Phys. Rev. B 1996, 54, 11169-11186.
[61] G. Kresse and J. Furthmuller, Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set, Comput. Mater. Sci. 1996, 6, 15–50.
[62] J. P. Perdew, K. Burke, and M. Ernzerhof, Generalized Gradient Approximation Made Simple, Phys. Rev. Lett. 1996, 77, 3865–3868.
[63] K.-H. Lin, H.-Y. Cheng, C.-Y. Yang, H.-W. Li, C.-W. Chang, S.-W. Chu, Phonon dynamics of single nanoparticles studied using confocal pump-probe backscattering, Appl. Phys. Lett., 2018, 113, 171906.
[64] G. Liang, Y. Wang, L. Han, Z. X. Yang, Q. Xin, Z. R. Kudrynskyi, Z. D. Kovalyuk, A. Patane, A. Song, Improved Performance of InSe Field-Effect Transistors by Channel Encapsulation, Semicond. Sci. Technol., 2018, 33, 1-5.
[65] O. A. Balitskii, N. N. Berchenko, V.P. Savchyn, J. M. Stakhira, Characteristics of Phase Formation during Indium Selenides Oxidation, Mater. Chem. Phys., 2000, 65, 130–135.
[66] X. Wang, J. B. Xu, C. Wang, J. Du, W. Xie, HighPerformance Graphene Devices on SiO2/Si Substrate Modified by Highly Ordered Self-Assembled Monolayers, Adv. Mater., 2011, 23, 2464–2468.
[67] Y. Guo, X. Wei, J. Shu, B. Liu, J. Yin, C. Guan, Y. Han, S. Gao, Q. Chen, Charge Trapping at the MoS2-SiO2 interface and Its Effects on the Characteristics of MoS2 metal-Oxide-Semiconductor Field Effect Transistors, Appl. Phys. Lett. 2015, 106, 103109.
[68] M. Y. Chan, K. Komatsu, S. L. Li, Y. Xu, P. Darmawan, H. Kuramochi, S. Nakaharai, A. Aparecido-Ferreira, K. Watanabe, T. Taniguchi and K. Tsukagoshi, Suppression of Thermally Activated Carrier Transport in Atomically Thin MoS2 on Crystalline Hexagonal Boron Nitride Substrates, Nanoscale 2013, 5, 9572–9576.
[69] C.-Y. Yang, C.-T. Chia, H.-Y. Chen, S. Gwo, K.-H. Lin, Ultrafast carrier dynamics in GaN nanorods, Appl. Phys. Lett., 2014, 105, 212105.
[70] C. Ping, B. Yue, and Q. Zhi, Structural and Photoluminescence Properties of Mn-Doped ZnO Nanocolumns Grown by Cathodic Electrodeposition, Rare Met. Mater. Eng. 2016, 45, 326–328.
[71] T. IKari, S. Shigetomi, K. Hashimoto, Crystal Structure and Raman Spectra of InSe, Phys. Stat. Sol., 1982, 111, 477.
[72] L. Shi, Q. Zhou, Y. Zhao, Y. Ouyang, C. Ling, Q. Li and J. Wang, Oxidation Mechanism and Protection Strategy of Ultrathin Indium Selenide: Insight from Theory, J. Phys. Chem. Lett. 2017, 8, 4368–4373.
[73] K. J. Xiao, A. Carvalho and A. H. Castro Neto, Defects and Oxidation Resilience in InSe, Phys. Rev. B, 2017, 96, 1–8.
[74] A.-J. Jeon, S.-J. Kim, S.-H. Lee and C.-Y. Kang, Effect of Indium Content on the Melting Point, Dross, and Oxidation Characteristics of Sn-2Ag-3Bi-XIn Solders, J. Electron. Packag. 2013, 135, 021006.
[75] I. Miyake, T. Tanpo and C. Tatsuyama, XPS study on the oxidation of InSe, Jpn. J. Appl. Phys. 1984, 23, 172-178.
[76] C. Donley, D. Dunphy, D. Paine, C. Carter, K. Nebesny, P. Lee, D. Alloway and N. R. Armstrong, Characterization of IndiumTin Oxide Interfaces Using X-Ray Photoelectron Spectroscopy and Redox Processes of a Chemisorbed Probe Molecule: Effect of Surface Pretreatment Conditions, Langmuir 2002, 18, 450–457.
[77] C. M. Julien and M. Balkanski, Lithium reactivity with III–VI layered compounds, Mater. Sci. Eng. B, 2003, 100, 263–270.
[78] J. Heyd, G. E. Scuseria and M. Ernzerhof, Hybrid functionals based on a screened Coulomb potential, J. Chem. Phys., 2003, 118, 8207–8215.
[79] M. S. Hybertsen and S. G. Louie, Electron correlation in semiconductors and insulators: Band gaps and quasiparticle energies, Phys. Rev. B, 1986, 34, 5390–5413.
[80] P. Y. Yu and M. Cardona, Fundamentals of Semiconductors, (Springer, 1999).
[81] D. B. Velusamy, R. H. Kim, S. Cha, J. Huh, R. Khazaeinezhad, S. H. Kassani, G. Song, S. M. Cho, S. H. Cho, I. Hwang, J. Lee, K. Oh, H. Choi and C. Park, Flexible Transition Metal Dichalcogenide Nanosheets for Band-Selective Photodetection, Nat. Commun. 2015, 6, 1–11.
[82] G. Su, V. G. Hadjiev, P. E. Loya, J. Zhang, S. Lei, S. Maharjan, P. Dong, P. M. Ajayan, J. Lou, H. Peng, Chemical Vapor Deposition of Thin Crystals of Layered Semiconductor SnS2 for Fast Photodetection Application, Nano Lett., 2015, 15, 506-513.
[83] E. Muñoz, E. Monroy, J. A. Garrido, I. Izpura, F. J. Sánchez, M. A. Sànchez-García, E. Calleja, B. Beaumont, P. Gibart, Photoconductor gain mechanisms in GaN ultraviolet detectors, Appl. Phys. Lett., 1997, 71, 870-872.
[84] L. Liu, C. Yang, A. Patanè, Z. Yu, F. Yan, K. Wang, H. Lu, J. Li, L. Zhao, High-detectivity ultraviolet photodetectors based on laterally mesoporous GaN, Nanoscale, 2017, 9, 8142-8148.
[85] G. W. Mudd, S. A; Svatek, L. Hague, O. Makarovsky, Z. R. Kudrynskyi, C. J. Mellor, P. H. Beton, L. Eaves, K. S. Novoselov, Z. D. Kovalyuk, E. E. Vdovin, A. J. Marsden, N. R. Wilson, A. Patane, High Broad-Band Photoresponsivity of Mechanically Formed InSe Graphene van der Waals Heterostructures, Adv. Mater., 2015, 27, 3760-3766.
[86] W. Wu, L. Wang, R. Yu, Y. Liu, S. H. Wei, J. Hone and Z. L. Wang, Piezophototronic Effect in Single-Atomic-Layer MoS2 for Strain-Gated Flexible Optoelectronics, Adv. Mater., 2016, 28, 8463-8468.
[87] C. Song, F. Fan, N. Xuan, S. Huang, G. Zhang, C. Wang, Z. Sun, H. Wu and H. Yan, Largely Tunable Band Structures of Few-Layer InSe by Uniaxial Strain, ACS Appl. Mater. Interfaces, 2018, 10, 3994-4000.
[88] H. Zou, X. Li, W. Peng, W. Wu, R. Yu, C. Wu, W. Ding, F. Hu, R. Liu, Y. Zi and Z. L. Wang, Piezo-Phototronic Effect on Selective Electron or Hole Transport through Depletion Region of Vis-NIR Broadband Photodiode, Adv. Mater., 2017, 29, 1701412.
[89] G. Haider, P. Roy, C. W. Chiang, W. C. Tan, Y. R. Liou, H. T. Chang, C. T. Liang, W. H. Shih and Y. F. Chen, Electrical-Polarization-Induced Ultrahigh Responsivity Photodetectors Based on Graphene and Graphene Quantum Dots, Adv. Funct. Mater., 2016, 26, 620-628.
[90] W. Li and J. Li, Piezoelectricity in two-dimensional group-III monochalcogenides, Nano Res., 2015, 8, 3796-3802.
[91] K. A. N. Duerloo, M. T. Ong and E. J. Reed, Intrinsic Piezoelectricity in Two-Dimensional Materials, J. Phys. Chem. Lett., 2012, 3, 2871-2876.
[92] J. H. Lee, J. Y. Park, E. B. Cho, T. Y. Kim, S. A. Han, T. H. Kim, Y. Liu, S. K. Kim, C. J. Roh, H. J. Yoon, H. Ryu, W. Seung, J. Lee and S. W. Kim, Reliable Piezoelectricity in Bilayer WSe2 for Piezoelectric Nanogenerators, Adv. Mater., 2017, 29, 1607.
[93] K. H. Michel and B. Verberck, Theory of phonon dispersions and piezoelectricity in multilayers of hexagonal boron-nitride, Phys. Status Solidi Basic Res., 2011, 248, 2720-2723.
[94] X. Wang, H. Tian, W. Xie, Y. Shu, W. T. Mi, M. A. Mohammad, Q. Y. Xie, Y. Yang, J. Bin Xu and T. L. Ren, Observation of a giant two-dimensional band-piezoelectric effect on biaxial-strained graphene, NPG Asia Mater., 2015, 7, e154.
[95] W. Wu, L. Wang, Y. Li, F. Zhang, L. Lin, S. Niu, D. Chenet, X. Zhang, Y. Hao, T. F. Heinz, J. Hone and Z. L. Wang, Piezoelectricity of single-atomic-layer MoS2 for energy conversion and piezotronics, Nature, 2014, 514, 470-474.
[96] H. Zhu, Y. Wang, J. Xiao, M. Liu, S. Xiong, Z. J. Wong, Z. Ye, Y. Ye, X. Yin and X. Zhang, Piezoelectricity of single-atomic-layer MoS2 for energy conversion and piezotronics, Nat. Nanotechnol., 2015, 10, 151-155.
[97] R. Fei, W. Li, J. Li and L. Yang, Giant piezoelectricity of monolayer group IV monochalcogenides: SnSe, SnS, GeSe, and GeS, Appl. Phys. Lett. 2015, 107, 173104.
[98] D. A. Bandurin, A. V. Tyurnina, G. L. Yu, A. Mishchenko, V. Zólyomi, S. V. Morozov, R. K. Kumar, R. V. Gorbachev, Z. R. Kudrynskyi, S. Pezzini, Z. D. Kovalyuk, U. Zeitler, K. S. Novoselov, A. Patane, L. Eaves, I. V. Grigorieva, V. I. Falko, A. K. Geim and Y. Cao, High electron mobility, quantum Hall effect and anomalous optical response in atomically thin InSe, Nat. Nanotechnol. 2017, 12, 223-227.
[99] D. T. Do, S. D. Mahanti and C. W. Lai, Spin splitting in 2D monochalcogenide semiconductors, Sci. Rep., 2015, 5, 17044.
[100] B. Marí, A. Segura and A. Chevy, Tin-related shallow donor in indium selenide, Appl. Phys. A, 1988, 46, 125-129.
[101] R. B. Jacobs-Gedrim, M. Shanmugam, N. Jain, C. A. Durcan, M. T. Murphy, T. M. Murray, R. J. Matyi, R. L. Moore, B. Yu, Extraordinary Photoresponse in Two-Dimensional In2Se3 Nanosheets, ACS Nano, 2014, 8, 514-521.
[102] W. Choi, M. Y. Cho, A. Konar, J. H. Lee, G. B. Cha, S. C. Hong, S. Kim, J. Kim, D. Jena, J. Joo, S. Kim, High-Detectivity Multilayer MoS2 Phototransistors with Spectral Response from Ultraviolet to Infrared, Adv. Mater., 2012, 24, 5832-5836.
[103] H. J. Conley, B. Wang, J. I. Ziegler, R. F. Haglund, S. T. Pantelides, K. I. Bolotin, Bandgap Engineering of Strained Monolayer and Bilayer MoS2, Nano Lett., 2013, 13, 3626-3630.
[104] X. Han, M. Chen, C. Pan, Z. L. Wang, Progress in piezo-phototronic effect enhanced photodetectors, J. Mater. Chem. C, 2016, 4, 11341-11354.
[105] S. Yang, N. Lu, Gauge Factor and Stretchability of Silicon-on-Polymer Strain Gauges, Sensors (Switzerland), 2013, 13, 8577-8594.
[106] T. J. Wieting, J. L. Verble, Interlayer Bonding and the Lattice Vibrations of β–GaSe, Phys. Rev. B, 1972, 5, 1473-1479.
[107] J. F. Sánchez-Royo, G. Muñoz-Matutano, M. Brotons-Gisbert, J. P. Martínez-Pastor, A. Segura, A. Cantarero, R. Mata, J. Canet-Ferrer, G. Tobias, E. Canadell, J. Marques-Hueso, B. D. Gerard, Electronic structure, optical properties, and lattice dynamics in atomically thin indium selenide flakes, Nano Res. 2014, 7, 1556-1568.
[108] M. Zolfaghari, K. P. Jain, H. S. Mavi, M. Balkanski, C. Julien, A. Chevy, Raman investigation of InSe doped with GaS, Mater. Sci. Eng. B, 1996, 38, 161-170.
[109] S. Zhao, H. Wang, Y. Zhou, L. Liao, Y. Jiang, X. Yang, G. Chen, M. Lin, Y. Wang, H. Peng, Z. Liu, Controlled synthesis of single-crystal SnSe nanoplates, Nano Res., 2015, 8, 288-295.
[110] H. R. Chandrasekhar, R. G. Humphreys, U. Zwick, M. Cardona, Infrared and Raman spectra of the IV-VI compounds SnS and SnSe, Phys. Rev. B, 1977, 15, 2177-2183.
[111] R. M. Badger, A Relation Between Internuclear Distances and Bond Force Constants, J.Chem.Phys., 1934, 2, 128.
[112] M. Huang, H. Yan, C. Chen, D. Song, T. F. Heinz, J. Hone, Phonon softening and crystallographic orientation of strained graphene studied by Raman spectroscopy, Proc. Natl. Acad. Sci., 2009, 106, 7304-7308.
[113] O. Frank, M. Mohr, J. Maultzsch, C. Thomsen, I. Riaz, R. Jalil, K. S. Novoselov, G. Tsoukleri, J. Parthenios, K. Papagelis, L. Kavan, C. Galiotis, Raman 2D-Band Splitting in Graphene: Theory and Experiment, ACS Nano, 2011, 5, 2231-2239.
[114] Z. Dai, L. Liu, Z. Zhang, Strain Engineering of 2D Materials: Issues and Opportunities at the Interface, Adv. Mater. 2019, 31, 1805417.
[115] D. S. Schulman, A. J. Arnold, S. Das, Contact Engineering for 2D Materials and Devices, Chem. Soc. Rev. 2018, 47, 3037–3058.
[116] S. Lei, X. Wang, B. Li, J. Kang, Y. He, A. George, L. Ge, Y. Gong, P. Dong, Z. Jin, G. Brunetto, W. Chen, Z.-T. Lin, R. Baines, D. S. Galvão, J. Lou, E. Barrera, K. Banerjee, R. Vajtai, P. Ajayan, Surface Functionalization of Two-Dimensional Metal Chalcogenides by Lewis Acid-Base Chemistry, Nat. Nanotechnol., 2016, 11, 465–471.
[117] P. Luo, F. Zhuge, Q. Zhang, Y. Chen, L. Lv, Y. Huang, H. Li, T. Zhai, Doping Engineering and Functionalization of Two-Dimensional Metal Chalcogenides, Nanoscale Horiz., 2019, 4, 26–51.
[118] C. R. Paul Inbaraj, V. K. Gudelli, R. J. Mathew, R. K. Ulaganathan, R. Sankar, H. Y. Lin, H.-I. Lin, Y.-M. Liao, H.-Y. Cheng, K.-H. Lin, F. C. Chou, Y.-T. Chen, C.-H. Lee, G.-Y. Guo, Y.-F. Chen, Sn-Doping Enhanced Ultrahigh Mobility In1– xSnxSe Phototransistor, ACS Appl. Mater. Interfaces 2019, 11, 24269–24278.
[119] X. Liu, M. C. Hersam, Interface Characterization and Control of 2D Materials and Heterostructures, Adv. Mater. 2018, 30, 1801586.
[120] Y. Liu, N. O. Weiss, X. Duan, H. C. Cheng, Y. Huang, X. Duan, Van Der Waals Heterostructures and Devices, Nat. Rev. Mater. 2016, 1, 16042.
[121] X. Duan, C. Wang, A. Pan, R. Yu, X. Duan, Two-Dimensional Transition Metal Dichalcogenides as Atomically Thin Semiconductors: Opportunities and Challenges, Chem. Soc. Rev. 2015, 44, 8859–8876.
[122] R. Frisenda, A. J. Molina-Mendoza, T. Mueller, A. Castellanos-Gomez, H. S. J. Van Der Zant, Atomically Thin p-n Junctions Based on Two-Dimensional Materials, Chem. Soc. Rev. 2018, 47, 3339–3358.
[123] C. H. Lee, G. H. Lee, A. M. Van Der Zande, W. Chen, Y. Li, M. Han, X. Cui, G. Arefe, C. Nuckolls, T. F. Heinz, J. Guo, J. Hone, P. Kim, Atomically Thin p-n Junctions with van Der Waals Heterointerfaces, Nat. Nanotechnol. 2014, 9, 676–681.
[124] M. M. Furchi, A. Pospischil, F. Libisch, J. Burgdörfer, T. Mueller, Photovoltaic Effect in an Electrically Tunable Van der Waals Heterojunction, Nano Lett., 2014, 14, 4785–4791.
[125] R. Cheng, D. Li, H. Zhou, C. Wang, A. Yin, S. Jiang, Y. Liu, Y. Chen, Y. Huang, X. Duan, Electroluminescence and Photocurrent Generation from Atomically Sharp WSe2/MoS2 Heterojunction p-n Diodes, Nano Lett., 2014, 14, 5590–5597.
[126] Y. Gong, J. Lin, X. Wang, G. Shi, S. Lei, Z. Lin, X. Zou, G. Ye, R. Vajtai, B. I. Yakobson, H. Terrones, M. Terrones, B. K. Tay, J. Lou, S. T. Pantelides, Z. Liu, W. Zhou, P. M. Ajayan, Vertical and In-Plane Heterostructures from WS2/MoS2 Monolayers, Nat. Mater., 2014, 13, 1135–1142.
[127] J. Ahn, P. J. Jeon, S. R. A. Raza, A. Pezeshki, S. W. Min, D. K. Hwang, S. Im, Transition Metal Dichalcogenide Heterojunction PN Diode toward Ultimate Photovoltaic Benefits, 2D Mater., 2016, 3, 045011.
[128] S. Sucharitakul, N. J. Goble, U. R. Kumar, R. Sankar, Z. A. Bogorad, F. C. Chou, Y.-T. Chen, X. P. A. Gao, Intrinsic Electron Mobility Exceeding 103 cm2/(V s) in Multilayer InSe FETs, Nano Lett., 2015, 15, 3815–3819.
[129] E. Kress-Rogers, R. J. Nicholas, J. C. Portal, A. Chevy, Cyclotron Resonance Studies on Bulk and Two-Dimensional Conduction Electrons in InSe, Solid State Commun., 1982, 44, 379–383.
[130] G. W. Mudd, S. A. Svatek, T. Ren, A. Patanè, O. Makarovsky, L. Eaves, P. H. Beton, Z. D. Kovalyuk, G. V. Lashkarev, Z. R. Kudrynskyi and A. I. Dmitriev, Tuning the bandgap of exfoliated InSe nanosheets by quantum confinement, Adv. Mater. 2013, 25, 5714–5718.
[131] P. Ramasamy, D. Kwak, D.-H. Lim, H.-S. Ra, J.-S. Lee, Solution synthesis of GeS and GeSe nanosheets for high-sensitivity photodetectors, J. Mater. Chem. C, 2016, 4, 479-485.
[132] C. R. Dean, A. F. Young, I. Meric, C. Lee, L. Wang, S. Sorgenfrei, K. Watanabe, T. Taniguchi, P. Kim, K. L. Shepard, J. Hone, Boron Nitride Substrates for High-Quality Graphene Electronics., Nat. Nanotechnol., 2010, 5, 722–726.
[133] R. V. Gorbachev, I. Riaz, R. R. Nair, R. Jalil, L. Britnell, B. D. Belle, E. W. Hill, K. S. Novoselov, K. Watanabe, T. Taniguchi, Hunting for Monolayer Boron Nitride: Optical and Raman Signatures, Small, 2011, 7, 465-458.
[134] A. S. Mayorov, R. V. Gorbachev,S. V. Morozov, L. Britnell, R. Jalil, L. A. Ponomarenko, P. Blake, K. S. Novoselov, K. Watanabe, T. Taniguchi, A. K. Geim, Micrometer-Scale Ballistic Transport in Encapsulated Graphene at Room Temperature, Nano Lett., 2011, 11, 2396–2399.
[135] L. Britnell, R. V. Gorbachev, R. Jalil, B. D. Belle, F. Schedin, M. I. Katsnelson, L. Eaves, S. V. Morozov, A. S. Mayorov, N. M. R. Peres, A. H. Castro Neto, J. Leist, A. K. Geim, L. A. Ponomarenko, K. S. Novoselov, Electron Tunneling through Ultrathin Boron Nitride Crystalline Barriers, Nano Lett., 2012, 12, 1707–1710.
[136] S. Mouri, Y. Miyauchi, K. Matsuda, Tunable Photoluminescence of Monolayer MoS2 via Chemical Doping, Nano Lett., 2013, 13, 5944-5948.
[137] L. Tao, H. Li, Y. Gao, Z. Chen, L. Wang, Y. Deng, J. Zhang, J.-B. Xu, Deterministic and Etching-Free Transfer of Large-Scale 2D Layered Materials for Constructing Interlayer Coupled van der Waals Heterostructures, Adv. Mater. Technol., 2018, 3, 1700282.
[138] T. V. Shubina, W. Desrat, M. Moret, A. Tiberj, O. Briot, V. Y. Davydov, A. V. Platonov, M. A. Semina, B. Gil, InSe as a case between 3D and 2D layered crystals for excitons, Nat Commun., 2019, 10, 3479.
[139] I. Lee, S. Rathi, D. Lim, L. Li, J. Park, Y. Lee, K. S. Yi, K. P. Dhakal, J. Kim, C. Lee, G.-H. Lee, Y. D. Kim, J. Hone, S. J. Yun, D.-H. Youn, G.-H. Kim, Gate-Tunable Hole and Electron Carrier Transport in Atomically Thin Dual-Channel WSe2/MoS2 Heterostructure for Ambipolar Field-Effect Transistors, Adv. Mater., 2016, 28, 9519–9525.
[140] X. Zhou, X. Hu, S. Zhou, H. Song, Q. Zhang, L. Pi, L. Li, H. Li, J. Lü, T. Zhai, Tunneling Diode Based on WSe2/SnS2 Heterostructure Incorporating High Detectivity and Responsivity, Adv. Mater., 2018, 30, 1703286.
[141] H. Fang, C. Battaglia, C. Carraro, S. Nemsak, B. Ozdol, J. S. Kang, H. A. Bechtel, S. B. Desai, F. Kronast, A. A. Unal, G. Conti, C. Conlon, G. K. Palsson, M. C. Martin, A. M. Minor, C. S. Fadley, E. Yablonovitch, R. Maboudian, A. Javey, Strong Interlayer Coupling in van Der Waals Heterostructures Built from Single-Layer Chalcogenides, Proc. Natl. Acad. Sci., 2014, 111, 6198–6202.
[142] C.-Y. Yang, C.-T. Chia, H.-Y. Chen, S. Gwo, K.-H. Lin, Ultrafast carrier dynamics in GaN nanorods, Appl. Phys. Lett., 2014, 105, 212105.
[143] C. Zhong, V. K. Sangwan, J. Kang, J. Luxa, Z. Sofer, M. C. Hersam, E. A. Weiss, Hot Carrier and Surface Recombination Dynamics in Layered InSe Crystals. J. Phys. Chem. Lett. 2019, 10, 493-499.
[144] T.-R. Kuo, H.-J. Liao, Y.-T. Chen, C.-Y. Wei, C.-C. Chang, Y.-C. Chen, Y.-H. Chang, J.-C. Lin, Y.-C. Lee, C.-Y. Wen, S.-S. Li, K.-H. Lin, D.-Y. Wang, Extended Visible to Near-Infrared Harvesting of Earth-Abundant FeS2–TiO2 Heterostructures for Highly Active Photocatalytic Hydrogen Evolution, Green Chem., 2018, 20, 1640-1647.
[145] P. Zhang, G. Zhu, Y. Shi, Y. Wang, J. Zhang, L. Du, D. Ding, Ultrafast Interfacial Charge Transfer of Cesium Lead Halide Perovskite Films CsPbX3 (X = Cl, Br, I) with Different Halogen Mixing. J. Phys. Chem. C 2018, 122, 27148-27155.
[146] C. Zhong, V. K. Sangwan, J. Kang, J. Luxa, Z. Sofer, M. C. Hersam, E. A. Weiss, Hot Carrier and Surface Recombination Dynamics in Layered InSe Crystals. J. Phys. Chem. Lett. 2019, 10, 493-499.
[147] C. Carlone, S. Jandl, H. R. Shanks, Optical Phonons and Crystalline Symmetry of InSe, Phys. Status Solidi, 1981, 103, 123–130.
[148] D. Tan, H. E. Lim, F. Wang, N. B. Mohamed, S. Mouri, W. Zhang, Y. Miyauchi, M. Ohfuchi, K. Matsuda, Anisotropic Optical and Electronic Properties of Two-Dimensional Layered Germanium Sulfide, Nano Res., 2017, 10, 546–555.
[149] C. Jin, J. Kim, J. Suh, Z. Shi, B. Chen, X. Fan, M. Kam, K. Watanabe, T. Taniguchi, S. Tongay, A. Zettl, J. Wu, F. Wang, Interlayer Electron-Phonon Coupling in WSe2/hBN Heterostructures, Nature Phys., 2017, 13, 127–131.
[150] L. Du, Y. Zhao, Z. Jia, M. Liao, Q. Wang, X. Guo, Z. Shi, R. Yang, K. Watanabe, T. Taniguchi, J. Xiang, D. Shi, Q. Dai, Z. Sun, G. Zhang, Strong and Tunable Interlayer Coupling of Infrared-Active Phonons to Excitons in van der Waals Heterostructures, Phys. Rev., B 2019, 99, 205410.
[151] L. Tao, H. Li, Y. Gao, Z. Chen, L. Wang, Y. Deng, J. Zhang, J.-B. Xu, Deterministic and Etching-Free Transfer of Large-Scale 2D Layered Materials for Constructing Interlayer Coupled van der Waals Heterostructures, Adv. Mater. Technol., 2018, 3, 1700282.
[152] K. Zhang, T. Zhang, G. Cheng, T. Li, S. Wang, W. Wei, X. Zhou, W. Yu, Y. Sun, P. Wang, D. Zhang, C. Zeng, X. Wang, W. Hu, H. J. Fan, G. Shen, X. Chen, X. Duan, K. Chang, N. Dai, Interlayer Transition and Infrared Photodetection in Atomically Thin Type-II MoTe2/MoS2 van Der Waals Heterostructures, ACS Nano, 2016, 10, 3852–3858.
[153] Z. Zheng, J. Yao, G. Yang, Self-Assembly of the Lateral In2Se3 /CuInSe2 Heterojunction for Enhanced Photodetection, ACS Appl. Mater. Interfaces, 2017, 9, 7288–7296.
[154] M.-Y. Li, Y. Shi, C.-C. Cheng, L.-S. Lu, Y.-C. Lin, H.-L. Tang, M.-L. Tsai, C.-W. Chu, K.-H. Wei, J.-H. He, W.-H. Chang, K. Suenaga, L.-J. Li, Epitaxial growth of a monolayer WSe2-MoS2 lateral p-n junction with an atomically sharp interface, Science, 2015, 349, 524–528.
[155] F. Wu, H. Xia, H. Sun, J. Zhang, F. Gong, Z. Wang, L. Chen, P. Wang, M. Long, X. Wu, J. Wang, W. Ren, X. Chen, W. Lu, W. Hu, AsP/InSe Van Der Waals Tunneling Heterojunctions with Ultrahigh Reverse Rectification Ratio and High Photosensitivity, Adv. Funct. Mater., 2019, 29, 1900314.
[156] C. R. Paul Inbaraj, R. J. Mathew, G. Haider, T.-P. Chen, R. K. Ulaganathan, R. Sankar, K. P. Bera, Y.-M. Liao, M. Kataria, H.-I. Lin, F. C. Chou, Y.-T. Chen, C.-H. Lee, Y.-F. Chen, Ultra-High Performance Flexible Piezopotential Gated In 1−x Sn x Se Phototransistor, Nanoscale, 2018, 10, 18642–18650.
[157] D. Jariwala, S. L. Howell, K. S. Chen, J. Kang, V. K. Sangwan, S. A. Filippone, R. Turrisi, T. J. Marks, L. J. Lauhon, M. C. Hersam, Hybrid, Gate-Tunable, van Der Waals p-n Heterojunctions from Pentacene and MoS2, Nano Lett., 2016, 16, 497–503.
[158] D. Sarkar, X. Xie, W. Liu, W. Cao, J. Kang, Y. Gong, S. Kraemer, P. M. Ajayan, K. A. Banerjee, Subthermionic Tunnel Field-Effect Transistor with an Atomically Thin Channel, Nature, 2015, 526, 91–95.
[159] Y. Hattori, T. Taniguchi, K. Watanabe, K. Nagashio, Determination of Carrier Polarity in Fowler−Nordheim Tunneling, ACS Appl. Mater. Interfaces, 2018, 10, 11732–11738.
[160] Z. Chen, Z. Zhang, J. Biscaras, A. Shukla, A High Performance Self-Driven Photodetector Based on a Graphene/InSe/MoS2 Vertical Heterostructure, J. Mater. Chem. C, 2018, 6, 12407–12412.
[161] G.-H. Lee, Y.-J. Yu, C. G. Lee, C. Dean, K. L. Shepard, P. Kim, J. Hone, Electron tunneling through atomically flat and ultrathin hexagonal boron nitride, Appl. Phys. Lett., 2011, 99, 243114.
[162] L. Britnell, R. V. Gorbachev, R. Jalil, B. D. Belle, F. Schedin, A. Mishchenko, T. Georgiou, M. I. Katsnelson, L. Eaves, S. V. Morozov, N. M. R. Peres, J. Leist, A. K. Geim, K. S. Novoselov, L. A. Ponomarenko, Field-Effect Tunneling Transistor Based on Vertical Graphene Heterostructures, Science, 2012, 335, 947-950.
[163] C. Palacios-Berraquero, M. Barbone, D. M. Kara, X. Chen, I. Goykhman, D. Yoon, A. K. Ott, J. Beitner, K. Watanabe, T. Taniguchi, A. C. Ferrari, M. Atatüre. Atomically thin quantum light-emitting diodes. Nat Commun., 2016, 7, 12978.
[164] Q. A. Vu, Y. S. Shin, Y. R. Kim, V. L. Nguyen, W. T. Kang, H. Kim, D. H. Luong, I. M. Lee, K. Lee, D.-S. Ko, J. Heo, S. Park, Y. H. Lee, W. J. Yu, Two-terminal floating-gate memory with van der Waals heterostructures for ultrahigh on/off ratio. Nat Commun., 2016, 7, 12725.
[165] C. Xie, C. Mak, X. Tao, F. Yan, Photodetectors Based on Two-Dimensional Layered Materials Beyond Graphene, Adv. Funct. Mater., 2017, 27, 1603886.
[166] C. Wang, L. Peng, Q. Qian, J. Y. Du, S. F. Wang, Y. C. Huang, Tuning the Carrier Confinement in GeS/Phosphorene van der Waals Heterostructures, Small, 2018, 14, 1703536.
[167] Z. Bao, X. Chen, Flexible and Stretchable Devices, Adv. Mater., 2016, 28, 4177–4179.
[168] D. Akinwande, N. Petrone, J. Hone, Two-Dimensional Flexible Nanoelectronics. Nat. Commun. 2014, 5, 5678.
[169] Y. Wakayama, R. Hayakawa, Antiambipolar Transistor: A Newcomer for Future Flexible Electronics, Adv. Funct. Mater., 2020, 30, 1–11.
[170] E. Wu, Y. Xie, Q. Liu, X. Hu, J. Liu, D. Zhang, C. Zhou, Photoinduced Doping to Enable Tunable and High-Performance Anti-Ambipolar MoTe2/MoS2 Heterotransistors, ACS Nano, 2019, 13, 5430–5438.
[171] Y. Li, Y. Wang, L. Huang, X. Wang, X. Li, H. X. Deng, Z. Wei, J. Li, Anti-Ambipolar Field-Effect Transistors Based on Few-Layer 2D Transition Metal Dichalcogenides, ACS Appl. Mater. Interfaces, 2016, 8, 15574–15581.
[172] C. J. Park, H. J. Park, J. Y. Lee, J. Kim, C. H. Lee, J. Joo, Photovoltaic Field-Effect Transistors Using a MoS2 and Organic Rubrene van der Waals Hybrid, ACS Appl. Mater. Interfaces, 2018, 10, 29848–29856.
[173] J. Dong, F. Liu, F. Wang, J. Wang, M. Li, Y. Wen, L. Wang, G. Wang, J. He, C. Jiang, Configuration-Dependent Anti-Ambipolar van Der Waals p-n Heterostructures Based on Pentacene Single Crystal and MoS2, Nanoscale, 2017, 9, 7519–7525.
[174] A. Nourbakhsh, A. Zubair, M. S. Dresselhaus, T. Palacios, Transport Properties of a MoS2/WSe2 Heterojunction Transistor and Its Potential for Application, Nano Lett., 2016, 16, 1359–1366.
[175] Y. Wang, W. X. Zhou, L. Huang, C. Xia, L. M. Tang, H. X. Deng, Y. Li, K. Q. Chen, J. Li, Z. Wei, Light Induced Double “on” State Anti-Ambipolar Behavior and Self-Driven Photoswitching in p-WSe2/n-SnS2 Heterostructures, 2D Mater., 2017, 4, 025097.
[176] K. Kobashi, R. Hayakawa, T. Chikyow, Y. Wakayama, Device Geometry Engineering for Controlling Organic Antiambipolar Transistor Properties, J. Phys. Chem. C, 2018, 122, 6943–6946.
[177] S. H. Yang, Y. T. Yao, Y. Xu, C. Y. Lin, Y. M. Chang, Y.W. Suen, H. Sun, C. H. Lien, W. Li, Y. F. Lin, Atomically Thin van Der Waals Tunnel Field-Effect Transistors and Its Potential for Applications, Nanotechnology, 2019, 30, 105201.
[178] T. Roy, M. Tosun, X. Cao, H. Fang, D. H. Lien, P. Zhao, Y. Z. Chen, Y. L. Chueh, J. Guo, A. Javey, Dual-Gated MoS2/WSe2 van der Waals Tunnel Diodes and Transistors, ACS Nano, 2015, 9, 2071–2079.
[179] J. Jiang, J. Li, Y. Li, J. Duan, L. Li, Y. Tian, Z. Zong, H. Zheng, X. Feng, Q. Li, H. Liu, Y. Zhang, T. L. Ren, L. Han, Stable InSe Transistors with High-Field Effect Mobility for Reliable Nerve Signal Sensing, npj 2D Mater. Appl., 2019, 3, 29.
[180] A. D. Bartolomeo, F. Urban, M. Passacantando, N. McEvoy, L. Peters, L. Iemmo, G. Luongo, F. Romeo, F. Giubileo, A WSe2 Vertical Field Emission Transistor, Nanoscale, 2019, 11, 1538–1548.
[181] H. Zhou, C. Wang, J. C. Shaw, R. Cheng, Y. Chen, X. Huang, Y. Liu, N. O. Weiss, Z. Lin, Y. Huang, X. Duan, Large Area Growth and Electrical Properties of p-Type WSe2 Atomic Layers, Nano Lett., 2015, 15, 709–713.
[182] P. C. Yeh, W. Jin, N. Zaki, D. Zhang, J. T. Liou, J. T. Sadowski, A. Al-Mahboob, J. I. Dadap, I. P. Herman, P. Sutter, R. M. Osgood, Layer-Dependent Electronic Structure of an Atomically Heavy Two-Dimensional Dichalcogenide, Phys. Rev. B - Condens. Matter Mater. Phys., 2015, 91, 1–6.
[183] W. Zhao, Z. Ghorannevis, L. Chu, M. Toh, C. Kloc, P. H. Tan, G. Eda, Evolution of Electronic Structure in Atomically Thin Sheets of WS2 and WSe2, ACS Nano, 2013, 7, 791–797.
[184] A. Varghese, D. Saha, K. Thakar, V. Jindal, S. Ghosh, N. V. Medhekar, S. Ghosh, S. Lodha, Near-Direct Bandgap WSe2/ReS2 Type-II Pn Heterojunction for Enhanced Ultrafast Photodetection and High-Performance Photovoltaics, Nano Lett., 2020, 20, 1707–1717.
[185] C. R. Paul Inbaraj, R. J. Mathew, R. K. Ulaganathan, R. Sankar, M. Kataria, H. Y. Lin, H.-Y. Cheng, K.-H. Lin, H.-I. Lin, Y.-M. Liao, F. C. Chou, Y.-T. Chen, C.-H. Lee, Y. F. Chen, Modulating Charge Separation with Hexagonal Boron Nitride Mediation in Vertical Van Der Waals Heterostructures, ACS Appl. Mater. Interfaces, 2020, 12, 26213–26221.
[186] P. Tonndorf, R. Schmidt, P. Böttger, X. Zhang, J. Börner, A. Liebig, M. Albrecht, C. Kloc, O. Gordan, D. R. T. Zahn, S. Michaelis de Vasconcellos, R. Bratschitsch, Photoluminescence Emission and Raman Response of Monolayer MoS2, MoSe2, and WSe2, Opt. Express, 2013, 21, 4908–4916.
[187] S. B. Desai, G. Seol, J. S. Kang, H. Fang, C. Battaglia, R. Kapadia, J. W. Ager, J. Guo, A. Javey, Strain-Induced Indirect to Direct Bandgap Transition in Multilayer WSe2, Nano Lett., 2014, 14, 4592–4597.
[188] P. Lin, L. Zhu, D. Li, L. Xu, C. Pan, Z. Wang, Piezo-Phototronic Effect for Enhanced Flexible MoS2/WSe2 van Der Waals Photodiodes, Adv. Funct. Mater., 2018, 28, 1802849.
[189] Y. Li, T. Wang, M. Wu, T. Cao, Y. Chen, R. Sankar, R. K. Ulaganathan, F. C. Chou, C. Wetzel, C. Y. Xu, S. G. Louie, S. F. Shi, Ultrasensitive Tunability of the Direct Bandgap of 2D InSe Flakes via Strain Engineering, 2D Mater., 2018, 5, 021002.
[190] W. Zhao, R. M. Ribeiro, M. Toh, A. Carvalho, C. Kloc, A. H. Castro Neto, G. Eda, Origin of Indirect Optical Transitions in Few-Layer MoS2, WS2, and WSe2, Nano Lett., 2013, 13, 5627–5634.
[191] S. B. Desai, G. Seol, J. S. Kang, H. Fang, C. Battaglia, R. Kapadia, J. W. Ager, J. Guo, A. Javey, Strain-Induced Indirect to Direct Bandgap Transition in Multilayer WSe2, Nano Lett., 2014, 14, 4592–4597.
[192] K. P. Dhakal, S. Roy, H. Jang, X. Chen, W. S. Yun, H. Kim, J. Lee, J. Kim, J. H. Ahn, Local Strain Induced Band Gap Modulation and Photoluminescence Enhancement of Multilayer Transition Metal Dichalcogenides, Chem. Mater., 2017, 29, 5124–5133.
[193] S. Lukman, L. Ding, L. Xu, Y. Tao, A. C. Riis-Jensen, G. Zhang, Q. Y. S. Wu, M. Yang, S. Luo, C. Hsu, L. Yao, G. Liang, H. Lin, Y. W. Zhang, K. S. Thygesen, Q. J. Wang, Y. Feng, J. Teng, High Oscillator Strength Interlayer Excitons in Two-Dimensional Heterostructures for Mid-Infrared Photodetection, Nat. Nanotechnol., 2020, 15, 675–682.
[194] T. Guo, C. Ling, T. Zhang, H. Li, X. Li, X. Chang, L. Zhu, L. Zhao, Q. Xue, High-Performance WO3-:X-WSe2/SiO2/n-Si Heterojunction near-Infrared Photodetector via a Homo-Doping Strategy, J. Mater. Chem. C, 2018, 6, 5821–5829.
[195] K. Zhang, M. Peng, W. Wu, J. Guo, G. Gao, Y. Liu, J. Kou, R. Wen, Y. Lei, A. Yu, Y. Zhang, J. Zhai, Z. L. Wang, A Flexible P-CuO/n-MoS2 Heterojunction Photodetector with Enhanced Photoresponse by the Piezo-Phototronic Effect, Mater. Horizons, 2017, 4, 274–280.
[196] A. K. Paul, M. Kuiri, D. Saha, B. Chakraborty, S. Mahapatra, A. K. Sood and A. Das, Photo-tunable transfer characteristics in MoTe2–MoS2 vertical heterostructure, npj 2D Mater Appl., 2017, 1, 17.
[197] H. Han, C.-H. Kim, Prediction of a Two-Transistor Vertical QNOT Gate, Appl. Sci., 2020, 10, 7597.