作為下一代氣體感測材料的候選之一，二維（2D）材料展現出良好的前景。然而，目前如何實現高品質和大規模生產2D器件仍然面臨一系列技術問題。對此，本研究採用之電漿輔助硒化製程被認為有望解決這個問題。作為硒化反應過程中的一個重要參數，輸運氣體的組成比例可以大幅影響生長材料的氣體感測性能。本研究重點研究了MoSe2和SnSe2在硒化過程中的輸運氣體比例對生長材料氣感性能的影響。
對MoSe2的研究主要討論了使用離子化氮氫混氣作為載氣的電漿輔助硒化反應製備氮掺雜薄膜的方法。通過控制載氣中氮氫相對流量，可以調節薄膜中的氮掺雜量。結果表明，在富含N2的環境中進行氮掺雜時，與NO2相比，薄膜對NH3的靈敏度更佳。這種改善的選擇性可以歸因於能隙能級更接近NH3的氧化電位，這有利於從NH3分子中獲得電子。相對的，還原能量更高的NO2對氣體分子抓取電子起到阻礙作用。因此，在生長過程中對輸運氣體的調控可以調節感測材料的選擇性，這一現象擴展了基於2D材料的氣體感測器的應用潛力。
在對SnSe2的研究中，利用電漿輔助硒化製程製備了用於NO2氣體感測的含氧SnSe2薄膜。通過降低反應過程中氮氣和氫氣混合氣中氫氣的比例，可以增加薄膜中的氧含量。當氫氣比例設定為25%時，薄膜對NO2的氣體響應顯著增強，實現了100 ppb NO2下709%的響應。該感測器還表現出優異的穩定性，在相對濕度低於89%的情況下仍保持其響應。這些發現突出了含氧SnSe2薄膜作為下一代氣體感測器的巨大潛力。

Two-dimensional (2D) materials have shown promising prospects as next-generation gas sensing materials. However, the current technology for high-quality and large-scale production of 2D devices is still not well-developed. The plasma-assisted selenization process holds the potential to address this issue. As an important parameter during the selenization reaction, the composition ratio of the transport gas significantly impacts the gas sensing performance of the grown materials. In this work, the research focuses on the study of MoSe2 and SnSe2 during the selenization process, investigating the influence of transport gas ratios.
The research on MoSe2 explores the fabrication of nitrogen-doped films using a plasma-assisted chemical vapor reaction furnace with ionized N2 and H2 carrier gas. By controlling the relative flow rate of carrier gas, the amount of nitrogen doping in the films is adjusted. The results demonstrate that the films exhibit enhanced sensitivity to NH3 compared to NO2 when nitrogen doping is conducted in a N2-rich environment. This improved sensitivity is attributed the valence band closer to the oxidation potential of NH3, which is favored to donate electrons from NH3 molecules, along with a larger electron affinity than the reduction energy of NO2 which hinders electron extraction toward gas molecules. The atmospheric modification during the growth process allows for tuning the sensing targets, expanding the application potential of 2D-material-based gas sensors.
In the study on SnSe2, oxygen-incorporated films for NO2 gas sensing are fabricated using a plasma-assisted selenization process. The oxygen content in the films is increased by reducing the proportion of hydrogen in the mixed gas of nitrogen and hydrogen during the reaction. The films exhibit significant enhancement in the gas response to NO2, reaching a remarkable 709% response at 100 ppb NO2 when the proportion of hydrogen is set at 25%. The sensor also demonstrates excellent stability, maintaining its response even under increased relative humidity levels below 89%. These findings highlight the great potential of oxygen-incorporated SnSe2 films as next-generation gas sensors.

Table of Contents
Abstract （中文） i
Abstract ii
Acknowledgement iv
Table of Contents v
List of Figures vii
Chapter 1 1
1. Introduction 1
1.1. Layered metal dichalcogenides (LMDs) 4
1.2. LMDs Fabrication 5
1.2.1. Mechanical Exfoliation 6
1.2.2. CVD 8
1.2.3. Hydrothermal Process 10
1.3. LMDs material based gas sensor 12
1.3.1. Background of global gas sensor market 12
1.3.2. Development of 2D materials based gas sensor 15
1.4. Plasma-assistant selenization process 18
1.4.1. Introduction of plasma-assistant selenization process 18
1.4.2. History of plasma-assistant selenization process 20
1.5. Objectives and Framwork 24
Chapter 2 26
2. Controllable Vertical Nitrogen Doping in MoSe2 for Selective Sensing 26
2.1. Introduction and background 26
2.2. Experimental Section 29
2.2.1. Fabrication of MoSe2 29
2.2.2. Characterizations 30
2.2.3. Fabrication and Measurement of Gas Sensors 31
2.2.4. Operando measurements 32
2.3. Results and discussion 33
2.3.1. The growth of MoSe2 33
2.3.2. Sensitivity of MoSe2 37
2.3.3. Selectivity of MoSe2 40
2.3.4. XPS Results of MoSe2 46
2.3.5. Band diagrams of MoSe2 and sensing mechanism 54
2.3.6. TEM Results of MoSe2 59
2.3.7. EXAFS Results of MoSe2 61
2.4. Conclusion 66
Chapter 3 68
3. Fabrication of Oxygen-Incorporated SnSe2 via Controllable Plasma-Assisted Selenization 68
3.1. Introduction 68
3.2. Experimental Section 71
3.2.1. Fabrication of the oxygen-incorporated SnSe2 film 71
3.2.2. Characterizations 73
3.2.3. Electrode construction and gas sensing measurements 74
3.3. Results and discussion 75
3.3.1. Growth of SnSe2 under different H2 concentrations 75
3.3.2. XRD and TEM results of SnSe2 79
3.3.3. Growth of SnSe2 under different temperatures 85
3.3.4. XPS Results of SnSe2 89
3.3.5. Sensitivity of SnSe2 gas sensor 92
3.3.6. Selectivity of SnSe2 gas sensor 98
3.3.7. Stability of SnSe2 gas sensor 100
3.3.8. Mechanism of SnSe2 gas sensor 104
3.4. Conclusion 107
Chapter 4 109
4. Summary and Outlook 109
4.1. Summary 109
4.2. Outlook 110
Reference 112

Reference
1. Kim, E.; Lee, S.; Kim, J. H.; Kim, C.; Byun, Y. T.; Kim, H. S.; Lee, T. Pattern recognition for selective odor detection with gas sensor arrays. Sensors 2012, 12 (12), 16262-16273.
2. Swan, M. Sensor mania! the internet of things, wearable computing, objective metrics, and the quantified self 2.0. Journal of Sensor and Actuator networks 2012, 1 (3), 217-253.
3. Chen, K.; Gao, W.; Emaminejad, S.; Kiriya, D.; Ota, H.; Nyein, H. Y. Y.; Takei, K.; Javey, A. Printed carbon nanotube electronics and sensor systems. Advanced Materials 2016, 28 (22), 4397-4414.
4. Yang, W.; Gan, L.; Li, H.; Zhai, T. Two-dimensional layered nanomaterials for gas-sensing applications. Inorganic Chemistry Frontiers 2016, 3 (4), 433-451.
5. Yang, S.; Jiang, C.; Wei, S.-h. Gas sensing in 2D materials. Applied Physics Reviews 2017, 4 (2), 021304.
6. Kumar, R.; Liu, X.; Zhang, J.; Kumar, M. Room-temperature gas sensors under photoactivation: from metal oxides to 2D materials. Nano-Micro Letters 2020, 12, 1-37.
7. Wu, T.-T.; Chang, C.-h.; Hsu, C.-H.; Tsai, W.-C.; Tsai, H.-S.; Yen, Y.-T.; Shen, C.-H.; Shieh, J.-M.; Chueh, Y.-L. 30× 40 cm2 flexible Cu (In, Ga) Se2 solar panel by low temperature plasma enhanced selenization process. Nano energy 2016, 24, 45-55.
8. Xiong, Y.; Xu, W.; Ding, D.; Lu, W.; Zhu, L.; Zhu, Z.; Wang, Y.; Xue, Q. Ultra-sensitive NH3 sensor based on flower-shaped SnS2 nanostructures with sub-ppm detection ability. Journal of hazardous materials 2018, 341, 159-167.
9. Guo, X.; Shi, Y.; Ding, Y.; He, Y.; Du, B.; Liang, C.; Tan, Y.; Liu, P.; Miao, X.; He, Y. Indium-doping-induced selenium vacancy engineering of layered tin diselenide for improving room-temperature sulfur dioxide gas sensing. Journal of Materials Chemistry A 2022, 10 (42), 22629-22637.
10. Aftab, S.; Hegazy, H. H. Emerging Trends in 2D TMDs Photodetectors and Piezo‐Phototronic Devices. Small 2023, 2205778.
11. Chen, R.-S.; Ding, G.; Zhou, Y.; Han, S.-T. Fermi-level depinning of 2D transition metal dichalcogenide transistors. Journal of Materials Chemistry C 2021, 9 (35), 11407-11427.
12. Lu, C.; Fang, R.; Chen, X. Single‐atom catalytic materials for advanced battery systems. Advanced Materials 2020, 32 (16), 1906548.
13. Lin, L.; Lei, W.; Zhang, S.; Liu, Y.; Wallace, G. G.; Chen, J. Two-dimensional transition metal dichalcogenides in supercapacitors and secondary batteries. Energy Storage Materials 2019, 19, 408-423.
14. Mondal, A.; Vomiero, A. 2D Transition Metal Dichalcogenides‐Based Electrocatalysts for Hydrogen Evolution Reaction. Advanced Functional Materials 2022, 32 (52), 2208994.
15. Chang, L.; Sun, Z.; Hu, Y. H. 1T phase transition metal dichalcogenides for hydrogen evolution reaction. Electrochemical Energy Reviews 2021, 4, 194-218.
16. Huo, C.; Yan, Z.; Song, X.; Zeng, H. 2D materials via liquid exfoliation: a review on fabrication and applications. Science bulletin 2015, 60 (23), 1994-2008.
17. Zhou, D.; Shu, H.; Hu, C.; Jiang, L.; Liang, P.; Chen, X. Unveiling the growth mechanism of MoS2 with chemical vapor deposition: from two-dimensional planar nucleation to self-seeding nucleation. Crystal Growth & Design 2018, 18 (2), 1012-1019.
18. Gautam, A. K.; Faraz, M.; Khare, N. Enhanced thermoelectric properties of MoS2 with the incorporation of reduced graphene oxide (RGO). Journal of Alloys and Compounds 2020, 838, 155673.
19. Choi, S.-J.; Kim, I.-D. Recent developments in 2D nanomaterials for chemiresistive-type gas sensors. Electronic Materials Letters 2018, 14, 221-260.
20. Qu, Y.; Medina, H.; Wang, S. W.; Wang, Y. C.; Chen, C. W.; Su, T. Y.; Manikandan, A.; Wang, K.; Shih, Y. C.; Chang, J. W. Wafer scale phase‐engineered 1T‐and 2H‐MoSe2/Mo core–shell 3D‐hierarchical nanostructures toward efficient electrocatalytic hydrogen evolution reaction. Advanced Materials 2016, 28 (44), 9831-9838.
21. Ai, Y.; Wu, S.-C.; Wang, K.; Yang, T.-Y.; Liu, M.; Liao, H.-J.; Sun, J.; Chen, J.-H.; Tang, S.-Y.; Wu, D. C. Three-dimensional molybdenum diselenide helical nanorod arrays for high-performance aluminum-ion batteries. ACS nano 2020, 14 (7), 8539-8550.
22. Chen, Y. Z.; Wang, S. W.; Su, T. Y.; Lee, S. H.; Chen, C. W.; Yang, C. H.; Wang, K.; Kuo, H. C.; Chueh, Y. L. Phase‐Engineered Type‐II Multimetal–Selenide Heterostructures toward Low‐Power Consumption, Flexible, Transparent, and Wide‐Spectrum Photoresponse Photodetectors. Small 2018, 14 (22), 1704052.
23. Su, T.-Y.; Chen, Y.-Z.; Wang, Y.-C.; Tang, S.-Y.; Shih, Y.-C.; Cheng, F.; Wang, Z. M.; Lin, H.-N.; Chueh, Y.-L. Highly sensitive, selective and stable NO 2 gas sensors with a ppb-level detection limit on 2D-platinum diselenide films. Journal of Materials Chemistry C 2020, 8 (14), 4851-4858.
24. Lin, W.-S.; Medina, H.; Su, T.-Y.; Lee, S.-H.; Chen, C.-W.; Chen, Y.-Z.; Manikandan, A.; Shih, Y.-C.; Yang, J.-H.; Chen, J.-H. Selection role of metal oxides into transition metal dichalcogenide monolayers by a direct selenization process. ACS applied materials & interfaces 2018, 10 (11), 9645-9652.
25. Medina, H.; Li, J.-G.; Su, T.-Y.; Lan, Y.-W.; Lee, S.-H.; Chen, C.-W.; Chen, Y.-Z.; Manikandan, A.; Tsai, S.-H.; Navabi, A. Wafer-scale growth of wse2 monolayers toward phase-engineered hybrid wo x/wse2 films with sub-ppb no x gas sensing by a low-temperature plasma-assisted selenization process. Chemistry of Materials 2017, 29 (4), 1587-1598.
26. Chen, Y.-Z.; Lee, S.-H.; Su, T.-Y.; Wu, S.-C.; Chen, P.-J.; Chueh, Y.-L. Phase-modulated 3D-hierarchical 1T/2H WSe 2 nanoscrews by a plasma-assisted selenization process as high performance NO gas sensors with a ppb-level detection limit. Journal of Materials Chemistry A 2019, 7 (39), 22314-22322.
27. Su, T. Y.; Medina, H.; Chen, Y. Z.; Wang, S. W.; Lee, S. S.; Shih, Y. C.; Chen, C. W.; Kuo, H. C.; Chuang, F. C.; Chueh, Y. L. Phase‐engineered PtSe2‐layered films by a plasma‐assisted selenization process toward all PtSe2‐based field effect transistor to highly sensitive, flexible, and wide‐spectrum photoresponse photodetectors. Small 2018, 14 (19), 1800032.
28. Kumar, S.; Jasuja, A. Air quality monitoring system based on IoT using Raspberry Pi. In 2017 International Conference on Computing, Communication and Automation (ICCCA), 5-6 May 2017, 2017; pp 1341-1346. DOI: 10.1109/CCAA.2017.8230005.
29. Walsh, P. T. Toxic Gas Sensing for the Workplace. Measurement and Control 1996, 29 (1), 5-12. DOI: 10.1177/002029409602900102 (acccessed 2022/01/13).
30. Freddi, S.; Emelianov, A. V.; Bobrinetskiy, I. I.; Drera, G.; Pagliara, S.; Kopylova, D. S.; Chiesa, M.; Santini, G.; Mores, N.; Moscato, U.; et al. Development of a Sensing Array for Human Breath Analysis Based on SWCNT Layers Functionalized with Semiconductor Organic Molecules. Advanced Healthcare Materials 2020, 9 (12), 2000377. DOI: https://doi.org/10.1002/adhm.202000377.
31. Zhang, L.; Khan, K.; Zou, J.; Zhang, H.; Li, Y. Recent Advances in Emerging 2D Material‐Based Gas Sensors: Potential in Disease Diagnosis. Advanced Materials Interfaces 2019, 6 (22), 1901329.
32. de la Hoz, R. E.; Schlueter, D. P.; Rom, W. N. Chronic lung disease secondary to ammonia inhalation injury: a report on three cases. American journal of industrial medicine 1996, 29 (2), 209-214.
33. GOUDARZI, G. R.; Mohammadi, M. J.; AHMADI, A. K.; NEISI, A.; Babaei, A. A.; Mohammadi, B.; SOLEYMANI, Z.; Geravandi, S. Estimation of health effects attributed to NO2 exposure using AirQ model. 2012.
34. Sharma, S. B.; Jain, S.; Khirwadkar, P.; Kulkarni, S. The effects of air pollution on the environment and human health. Indian Journal of Research in Pharmacy and Biotechnology 2013, 1 (3), 391-396.
35. Khan, M. A. H.; Rao, M. V.; Li, Q. Recent advances in electrochemical sensors for detecting toxic gases: NO2, SO2 and H2S. Sensors 2019, 19 (4), 905.
36. Dey, A. Semiconductor metal oxide gas sensors: A review. Materials Science and Engineering: B 2018, 229, 206-217.
37. Schmidt, H.; Giustiniano, F.; Eda, G. Electronic transport properties of transition metal dichalcogenide field-effect devices: surface and interface effects. Chemical Society Reviews 2015, 44 (21), 7715-7736.
38. Zheng, W.; Liu, X.; Xie, J.; Lu, G.; Zhang, J. Emerging van der Waals junctions based on TMDs materials for advanced gas sensors. Coordination Chemistry Reviews 2021, 447, 214151.
39. Panigrahi, P.; Hussain, T.; Karton, A.; Ahuja, R. Elemental substitution of two-dimensional transition metal dichalcogenides (MoSe2 and MoTe2): implications for enhanced gas sensing. ACS sensors 2019, 4 (10), 2646-2653.
40. Zhang, D.; Yang, Z.; Li, P.; Pang, M.; Xue, Q. Flexible self-powered high-performance ammonia sensor based on Au-decorated MoSe2 nanoflowers driven by single layer MoS2-flake piezoelectric nanogenerator. Nano Energy 2019, 65, 103974.
41. Ikram, M.; Liu, L.; Lv, H.; Liu, Y.; Rehman, A. U.; Kan, K.; Zhang, W.; He, L.; Wang, Y.; Wang, R. Intercalation of Bi2O3/Bi2S3 nanoparticles into highly expanded MoS2 nanosheets for greatly enhanced gas sensing performance at room temperature. Journal of hazardous materials 2019, 363, 335-345.
42. Rathi, K.; Pal, K. Fabrication of MoSe2–Graphene Hybrid Nanoflakes for Toxic Gas Sensor with Tunable Sensitivity. Advanced Materials Interfaces 2020, 7 (12), 2000140.
43. Liu, Q.; Weijun, X.; Wu, Z.; Huo, J.; Liu, D.; Wang, Q.; Wang, S. The origin of the enhanced performance of nitrogen-doped MoS2 in lithium ion batteries. Nanotechnology 2016, 27 (17), 175402.
44. Xie, D.; Xia, X.; Wang, Y.; Wang, D.; Zhong, Y.; Tang, W.; Wang, X.; Tu, J. Nitrogen‐Doped Carbon Embedded MoS2 Microspheres as Advanced Anodes for Lithium‐and Sodium‐Ion Batteries. Chemistry–A European Journal 2016, 22 (33), 11617-11623.
45. Tao, P.; He, J.; Shen, T.; Hao, Y.; Yan, J.; Huang, Z.; Xu, X.; Li, M.; Chen, Y. Nitrogen‐doped MoS2 foam for fast sodium ion storage. Advanced materials interfaces 2019, 6 (13), 1900460.
46. Yi, Y.; Sun, Z.; Li, C.; Tian, Z.; Lu, C.; Shao, Y.; Li, J.; Sun, J.; Liu, Z. Designing 3D biomorphic nitrogen‐doped MoSe2/graphene composites toward high‐performance potassium‐ion capacitors. Advanced Functional Materials 2020, 30 (4), 1903878.
47. Pan, S.; Cai, Z.; Yang, L.; Tang, B.; Xu, X.; Chen, H.; Ran, L.; Jing, B.; Zou, J. Exposure of sufficient edge sites on well-crystallized MoSe2 induced by nitrogen doping (Mo− Nx) for Pt: Enhanced co-catalytic activity and methanol tolerance for oxygen reduction. Energy 2018, 159, 11-20.
48. Deng, S.; Zhong, Y.; Zeng, Y.; Wang, Y.; Yao, Z.; Yang, F.; Lin, S.; Wang, X.; Lu, X.; Xia, X. Directional construction of vertical nitrogen‐doped 1T‐2H MoSe2/graphene shell/core nanoflake arrays for efficient hydrogen evolution reaction. Advanced materials 2017, 29 (21), 1700748.
49. Deng, S.; Yang, F.; Zhang, Q.; Zhong, Y.; Zeng, Y.; Lin, S.; Wang, X.; Lu, X.; Wang, C. Z.; Gu, L. Phase modulation of (1T‐2H)‐MoSe2/TiC‐C shell/core arrays via nitrogen doping for highly efficient hydrogen evolution reaction. Advanced Materials 2018, 30 (34), 1802223.
50. Ren, X.; Ma, Q.; Ren, P.; Wang, Y. Synthesis of nitrogen-doped MoSe2 nanosheets with enhanced electrocatalytic activity for hydrogen evolution reaction. International Journal of Hydrogen Energy 2018, 43 (32), 15275-15280.
51. Azcatl, A.; Qin, X.; Prakash, A.; Zhang, C.; Cheng, L.; Wang, Q.; Lu, N.; Kim, M. J.; Kim, J.; Cho, K. Covalent nitrogen doping and compressive strain in MoS2 by remote N2 plasma exposure. Nano letters 2016, 16 (9), 5437-5443.
52. Xia, Y.; Wang, B.; Zhang, J.; Feng, Y.; Li, B.; Ren, X.; Tian, H.; Xu, J.; Ho, W.; Xu, H. Hole doping in epitaxial MoSe2 monolayer by nitrogen plasma treatment. 2D Materials 2018, 5 (4), 041005.
53. Le, K.; Zhang, X.; Zhao, Q.; Liu, Y.; Yi, P.; Xu, S.; Liu, W. Controllably Doping Nitrogen into 1T/2H MoS2 Heterostructure Nanosheets for Enhanced Supercapacitive and Electrocatalytic Performance by Low-Power N2 Plasma. ACS Applied Materials & Interfaces 2021, 13 (37), 44427-44439.
54. Enujekwu, F. M.; Zhang, Y.; Ezeh, C. I.; Zhao, H.; Xu, M.; Besley, E.; George, M. W.; Besley, N. A.; Do, H.; Wu, T. N-doping enabled defect-engineering of MoS2 for enhanced and selective adsorption of CO2: A DFT approach. Applied Surface Science 2021, 542, 148556.
55. Roy, A.; Movva, H. C.; Satpati, B.; Kim, K.; Dey, R.; Rai, A.; Pramanik, T.; Guchhait, S.; Tutuc, E.; Banerjee, S. K. Structural and electrical properties of MoTe2 and MoSe2 grown by molecular beam epitaxy. ACS applied materials & interfaces 2016, 8 (11), 7396-7402.
56. Cho, B.; Kim, A. R.; Park, Y.; Yoon, J.; Lee, Y.-J.; Lee, S.; Yoo, T. J.; Kang, C. G.; Lee, B. H.; Ko, H. C. Bifunctional sensing characteristics of chemical vapor deposition synthesized atomic-layered MoS2. ACS applied materials & interfaces 2015, 7 (4), 2952-2959.
57. Ikram, M.; Liu, L.; Liu, Y.; Ullah, M.; Ma, L.; Wu, H.; Yu, H.; Wang, R.; Shi, K. Controllable synthesis of MoS 2@ MoO 2 nanonetworks for enhanced NO 2 room temperature sensing in air. Nanoscale 2019, 11 (17), 8554-8564.
58. Zong, B.; Li, Q.; Chen, X.; Liu, C.; Li, L.; Ruan, J.; Mao, S. Highly enhanced gas sensing performance using a 1T/2H Heterophase MoS2 field-effect transistor at room temperature. ACS Applied Materials & Interfaces 2020, 12 (45), 50610-50618.
59. Ikram, M.; Lv, H.; Liu, Z.; Khan, M.; Liu, L.; Raziq, F.; Bai, X.; Ullah, M.; Zhang, Y.; Shi, K. Rational design of MoS2/C3N4 hybrid aerogel with abundant exposed edges for highly sensitive NO2 detection at room temperature. Chemistry of Materials 2020, 32 (17), 7215-7225.
60. Yi, N.; Cheng, Z.; Li, H.; Yang, L.; Zhu, J.; Zheng, X.; Chen, Y.; Liu, Z.; Zhu, H.; Cheng, H. Stretchable, ultrasensitive, and low-temperature NO2 sensors based on MoS2@ rGO nanocomposites. Materials Today Physics 2020, 15, 100265.
61. Zheng, W.; Xu, Y.; Zheng, L.; Yang, C.; Pinna, N.; Liu, X.; Zhang, J. MoS2 Van der Waals p–n junctions enabling highly selective room‐temperature NO2 sensor. Advanced Functional Materials 2020, 30 (19), 2000435.
62. Cha, J.-H.; Choi, S.-J.; Yu, S.; Kim, I.-D. 2D WS 2-edge functionalized multi-channel carbon nanofibers: effect of WS 2 edge-abundant structure on room temperature NO 2 sensing. Journal of Materials Chemistry A 2017, 5 (18), 8725-8732.
63. Ko, K. Y.; Lee, S.; Park, K.; Kim, Y.; Woo, W. J.; Kim, D.; Song, J.-G.; Park, J.; Kim, J. H.; Lee, Z. High-Performance Gas Sensor Using a Large-Area WS2 x Se2–2 x Alloy for Low-Power Operation Wearable Applications. ACS Applied Materials & Interfaces 2018, 10 (40), 34163-34171.
64. Youn, D.-H.; Kim, B.-J.; Yun, S. J. Synthesis and gas sensing properties of WS2 nanocrystallites assembled hierarchical WS2 fibers by electrospinning. Nanotechnology 2019, 31 (10), 105602.
65. Zheng, Y.; Sun, L.; Liu, W.; Wang, C.; Dai, Z.; Ma, F. Tungsten oxysulfide nanosheets for highly sensitive and selective NH 3 sensing. Journal of Materials Chemistry C 2020, 8 (12), 4206-4214.
66. Jha, R. K.; Nanda, A.; Bhat, N. Ultrasonication assisted fabrication of a tungsten sulfide/tungstite heterostructure for ppb-level ammonia detection at room temperature. RSC Advances 2020, 10 (37), 21993-22001.
67. Zhang, S.; Nguyen, T. H.; Zhang, W.; Park, Y.; Yang, W. Correlation between lateral size and gas sensing performance of MoSe2 nanosheets. Applied Physics Letters 2017, 111 (16), 161603.
68. Chen, X.; Chen, X.; Han, Y.; Su, C.; Zeng, M.; Hu, N.; Su, Y.; Zhou, Z.; Wei, H.; Yang, Z. Two-dimensional MoSe2 nanosheets via liquid-phase exfoliation for high-performance room temperature NO2 gas sensors. Nanotechnology 2019, 30 (44), 445503.
69. Hong, Y.; Kang, W.-M.; Cho, I.-T.; Shin, J.; Wu, M.; Lee, J.-H. Gas-sensing characteristics of exfoliated WSe2 field-effect transistors. Journal of Nanoscience and Nanotechnology 2017, 17 (5), 3151-3154.
70. Mane, A.; Suryawanshi, M.; Kim, J.; Moholkar, A. Highly selective and sensitive response of 30.5% of sprayed molybdenum trioxide (MoO3) nanobelts for nitrogen dioxide (NO2) gas detection. Journal of colloid and interface science 2016, 483, 220-231.
71. Wu, J.; Wei, Y.; Ding, H.; Wu, Z.; Yang, X.; Li, Z.; Huang, W.; Xie, X.; Tao, K.; Wang, X. Green synthesis of 3D chemically functionalized graphene hydrogel for high-performance NH3 and NO2 detection at room temperature. ACS Applied Materials & Interfaces 2020, 12 (18), 20623-20632.
72. Bae, G.; Song, D. S.; Lim, Y. R.; Jeon, I. S.; Jang, M.; Yoon, Y.; Jeon, C.; Song, W.; Myung, S.; Lee, S. S. Chemical patterning of graphene via metal-assisted highly energetic electron irradiation for graphene homojunction-based gas sensors. ACS Applied Materials & Interfaces 2020, 12 (42), 47802-47810.
73. Hu, C.; Yuan, C.; Hong, A.; Guo, M.; Yu, T.; Luo, X. Work function variation of monolayer MoS2 by nitrogen-doping. Applied Physics Letters 2018, 113 (4), 041602.
74. Sanjinés, R.; Wiemer, C.; Almeida, J.; Levy, F. Valence band photoemission study of the Ti Mo N system. Thin Solid Films 1996, 290, 334-338.
75. Wang, C.; Yin, L.; Zhang, L.; Xiang, D.; Gao, R. Metal oxide gas sensors: sensitivity and influencing factors. sensors 2010, 10 (3), 2088-2106.
76. Krishna, K. G.; Parne, S.; Pothukanuri, N.; Kathirvelu, V.; Gandi, S.; Joshi, D. Nanostructured metal oxide semiconductor-based gas sensors: A comprehensive review. Sensors and Actuators A: Physical 2022, 113578.
77. Li, Q.; Zeng, W.; Li, Y. Metal oxide gas sensors for detecting NO2 in industrial exhaust gas: Recent developments. Sensors and Actuators B: Chemical 2022, 131579.
78. Buckley, D. J.; Black, N. C.; Castanon, E. G.; Melios, C.; Hardman, M.; Kazakova, O. Frontiers of graphene and 2D material-based gas sensors for environmental monitoring. 2D Materials 2020, 7 (3), 032002.
79. Jha, R. K.; Sakhuja, N.; Bhat, N. 2d nano materials for cmos compatible gas sensors. In 2019 34th Symposium on Microelectronics Technology and Devices (SBMicro), 2019; IEEE: pp 1-3.
80. Zhou, C.; Yang, W.; Zhu, H. Mechanism of charge transfer and its impacts on Fermi-level pinning for gas molecules adsorbed on monolayer WS2. The Journal of chemical physics 2015, 142 (21), 214704.
81. Kaul, A. B. Two-dimensional layered materials: Structure, properties, and prospects for device applications. Journal of Materials Research 2014, 29 (3), 348-361.
82. Chen, H.; Zhang, J.; Kan, D.; He, J.; Song, M.; Pang, J.; Wei, S.; Chen, K. The Recent Progress of Two-Dimensional Transition Metal Dichalcogenides and Their Phase Transition. Crystals 2022, 12 (10), 1381.
83. Zhang, C.; Ning, J.; Wang, B.; Guo, H.; Feng, X.; Shen, X.; Jia, Y.; Dong, J.; Wang, D.; Zhang, J. Hybridized 1T/2H-MoS 2/graphene fishnet tube for high-performance on-chip integrated micro-systems comprising supercapacitors and gas sensors. Nano Research 2021, 14, 114-121.
84. Lee, D.; Jang, A.-R.; Kim, J. Y.; Lee, G.; Lee, T. I.; Lee, J.-O.; Kim, J.-J. Phase-dependent gas sensitivity of MoS2 chemical sensors investigated with phase-locked MoS2. Nanotechnology 2020, 31 (22), 225504.
85. Camargo Moreira, O. s. L.; Cheng, W.-Y.; Fuh, H.-R.; Chien, W.-C.; Yan, W.; Fei, H.; Xu, H.; Zhang, D.; Chen, Y.; Zhao, Y. High selectivity gas sensing and charge transfer of SnSe2. ACS sensors 2019, 4 (9), 2546-2552.
86. Hwa, Y.; Seok, B.; Chee, S.-S. Correlating Morphology and NO2 Gas Detection at Room Temperature in Layered Tin Diselenide. Electronic Materials Letters 2023, 19 (2), 212-217.
87. Paolucci, V.; D’Olimpio, G.; Kuo, C.-N.; Lue, C. S.; Boukhvalov, D. W.; Cantalini, C.; Politano, A. Self-assembled SnO2/SnSe2 heterostructures: a suitable platform for ultrasensitive NO2 and H2 sensing. ACS Applied Materials & Interfaces 2020, 12 (30), 34362-34369.
88. Li, X.; Liu, W.; Huang, B.; Liu, H.; Li, X. Layered SnSe 2 microflakes and SnSe 2/SnO 2 heterojunctions for low-temperature chemiresistive-type gas sensing. Journal of Materials Chemistry C 2020, 8 (44), 15804-15815.
89. Paolucci, V.; De Santis, J.; Lozzi, L.; Giorgi, G.; Cantalini, C. Layered amorphous a-SnO2 gas sensors by controlled oxidation of 2D-SnSe2. Sensors and Actuators B: Chemical 2022, 350, 130890.
90. Li, T.; Zhang, D.; Pan, Q.; Tang, M.; Yu, S. UV enhanced NO2 gas sensing at room temperature based on coral-like tin diselenide/MOFs-derived nanoflower-like tin dioxide heteronanostructures. Sensors and Actuators B: Chemical 2022, 355, 131049.
91. Seo, J.; Nam, S. H.; Lee, M.; Kim, J.-Y.; Kim, S. G.; Park, C.; Seo, D.-W.; Kim, Y. L.; Kim, S. S.; Kim, U. J. Gate-controlled gas sensor utilizing 1D–2D hybrid nanowires network. IScience 2022, 25 (1), 103660.
92. Wang, T.; Wang, Y.; Sun, Q.; Zheng, S.; Liu, L.; Li, J.; Hao, J. Boosted interfacial charge transfer in SnO 2/SnSe 2 heterostructures: toward ultrasensitive room-temperature H 2 S detection. Inorganic Chemistry Frontiers 2021, 8 (8), 2068-2077.
93. Paolucci, V.; De Santis, J.; Ricci, V.; Lozzi, L.; Giorgi, G.; Cantalini, C. Bidimensional Engineered Amorphous a-SnO2 Interfaces: Synthesis and Gas Sensing Response to H2S and Humidity. ACS sensors 2022, 7 (7), 2058-2068.
94. Pawar, M.; Kadam, S.; Late, D. J. High‐Performance Sensing Behavior Using Electronic Ink of 2D SnSe2 Nanosheets. ChemistrySelect 2017, 2 (14), 4068-4075.
95. Tannarana, M.; Pataniya, P. M.; Bhakhar, S. A.; Solanki, G.; Valand, J.; Narayan, S.; Patel, K. D.; Jha, P. K.; Pathak, V. Humidity sensor based on two-dimensional SnSe2/MWCNT nanohybrids for the online monitoring of human respiration and a touchless positioning interface. ACS Sustainable Chemistry & Engineering 2020, 8 (33), 12595-12602.
96. D’Olimpio, G.; Genuzio, F.; Mentes, T. O.; Paolucci, V.; Kuo, C.-N.; Al Taleb, A.; Lue, C. S.; Torelli, P.; Farias, D.; Locatelli, A. Charge redistribution mechanisms in SnSe2 surfaces exposed to oxidative and humid environments and their related influence on chemical sensing. The Journal of Physical Chemistry Letters 2020, 11 (21), 9003-9011.
97. Cheng, W.-Y.; Fuh, H.-R.; Chang, C.-R. First-principles study for gas sensing of defective SnSe2 monolayers. Applied Sciences 2020, 10 (5), 1623.
98. Liu, J. S.; Li, X. H.; Guo, Y. X.; Qyyum, A.; Shi, Z. J.; Feng, T. C.; Zhang, Y.; Jiang, C. X.; Liu, X. F. SnSe2 nanosheets for subpicosecond harmonic mode‐locked pulse generation. Small 2019, 15 (38), 1902811.
99. Gong, X.; Wang, Y.; Hong, Q.; Liu, J.; Yang, C.; Zou, H.; Zhou, Y.; Huang, D.; Wu, H.; Zhou, Z. In-situ micro-Raman study of SnSe single crystals under atmosphere: Effect of laser power and temperature. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2022, 265, 120375.
100. Pham, A.-T.; Vu, T. H.; Cheng, C.; Trinh, T. L.; Lee, J.-E.; Ryu, H.; Hwang, C.; Mo, S.-K.; Kim, J.; Zhao, L.-d. High-quality SnSe2 single crystals: electronic and thermoelectric properties. ACS Applied Energy Materials 2020, 3 (11), 10787-10792.
101. Xie, J.; Zhang, J.; Li, S.; Grote, F.; Zhang, X.; Zhang, H.; Wang, R.; Lei, Y.; Pan, B.; Xie, Y. Controllable disorder engineering in oxygen-incorporated MoS2 ultrathin nanosheets for efficient hydrogen evolution. Journal of the American Chemical Society 2013, 135 (47), 17881-17888.
102. Ma, H.-P.; Yang, J.-H.; Yang, J.-G.; Zhu, L.-Y.; Huang, W.; Yuan, G.-J.; Feng, J.-J.; Jen, T.-C.; Lu, H.-L. Systematic study of the SiOx film with different stoichiometry by plasma-enhanced atomic layer deposition and its application in SiOx/SiO2 super-lattice. Nanomaterials 2019, 9 (1), 55.
103. Xia, C.; An, J.; Wei, S.; Jia, Y.; Zhang, Q. Electronic structures and optical properties of SnSe2 (1− x) O2x alloys. Computational materials science 2014, 95, 712-717.