在此份研究裡，超薄氮化銦氣體感測器透過使用非極性矽油的外部過濾方式來選擇性感測出次ppm級的氨氣，並應用於肝病的檢測上。就我們所知，實質未摻雜的超薄氮化銦外延層具有較好的電子特性像是狹窄的能隙（0.6-0.7eV）、優異的電子傳遞特性（電子遷移率>1000 cm2/V·s）、以及背景高電子密度（尤其是超過1×1018 cm−3），因而具有高敏感度、快速反應、短恢復時間，以及偵測極限可低於0.2ppm的特性，除此，更具有片密度達1013 cm−2數量級的強表面電子聚集層之異常現象。因此，我的研究目的便是使用超薄（~10nm）氮化銦外延層，開發出選擇性氣體感測器，結合矽油吸收劑在呼出氣體中同時含有丙酮、異戊二烯、乙腈等的環境下感測出氨氣，進而應用肝病檢測上。選擇非極性矽油作為吸收介質，其主要用來吸收實驗中最大干擾氣體丙酮，並讓目標氣體氨氣不會被吸收進而能暴露到超薄（~10nm）氮化銦外延層上，至於其他也存在人體呼出氣體中像是異戊二烯、乙腈、二甲基硫醚等干擾氣體，所含濃度皆遠小於丙酮，且異戊二烯是為非極性氣體，同樣可被矽油所吸收，因此其對於氮化銦氣體感測器的影響可以被忽略；而二甲基硫醚在呼出氣體中所佔的濃度極小，因此也不會被氮化銦氣體感測器所測得，是故選擇矽油作為吸收劑，能使其對於作為肝病檢測的超薄氮化銦氣體感測器應用上，大幅改善於呼出氣體中的氨氣選擇性，如圖1.21所示。此外，也會將呼出氣體中的氨氣及氨氣最大干擾氣體丙酮、異戊二烯、乙腈、二甲基硫醚等定量，使用T201 NH3分析儀測得呼出氣體VOCs中的氨氣含量，並透過GC-ATD-MS定量干擾氣體丙酮、異戊二烯、乙腈、二甲基硫醚等。

In this study, ultrathin InN gas sensor for selective sensing of sub-ppm ammonia gas by using an external filter of non-polar silicone oil for the liver malfunction application. As we know that ultrathin InN epilayer has higher sensitivity, fast response and recovery time, detection limit below the 0.2 ppm. It is because of the fact that ultrathin InN epilayer has superior electronic properties such as narrow band gap (0.6−0.7 eV), exceptional electron transport characteristics (mobility > 1000 cm2/V·s), and a background high electron density (typically in excess of 1×1018 cm−3) for the nominally undoped InN epilayer. Further, unusual phenomenon of a strong surface electron accumulation layer with a sheet density of the order of 1013 cm−2 occurs within a few nanometers from the InN surface. Here my objective is to develop selective gas sensor on the ultrathin (~10 nm) InN epilayer for ammonia gas in a combined matrix of interfrents in exhaled breath such as acetone, isoprene, acetonitrile for the liver malfunction application by using silicone oil absorbent. Here we are using non-polar silicone oil as an absorbing medium. The function of nonpolar silicone oil to absorbed our major interfering acetone gas and pass our target ammonia gas without absorption in silicone oil to further exposed on the ultrathin (~10 nm) InN epilayer. The selectivity of ultrathin (~10 nm) InN gas sensor for the exhaled breath ammonia gas will be improve by using nonpolar silicone oil as an absorbent for the liver malfunction application. But still there are other interferents present in human breath such as isoprene, acetonitrile, dimethyl sulfide (DMS) whose concentration is very small than acetone gas. Isoprene is a nonpolar gas, which will absorb in silicone oil. Therefore, the response of isoprene on InN gas sensor will be negligible. The concentration of DMS in exhaled breath is very small, therefore DMS will be not detected by InN gas sensor. Therefore, the selectivity of the ultrathin InN gas sensor will be improved by using nonpolar silicone oil for the ammonia gas for the liver malfunction application in Figure 1.21. Further, we will quantify exhaled breath ammonia gas as well as exhaled breath acetone, DMS, acetonitrile, isoprene etc. which act as major interferent for the ammonia gas in the liver malfunction application. We will use T201 NH3 analyzer to quantify the exhaled breath ammonia gas in combined matrix of exhaled breath VOCs. In addition, we will use GC-ATD-MS to quantify the major interfrent such as acetone, DMS, isoprene, acetonitrile etc.

CONTENTS
ACKNOWLEDGEMENT i
摘要 ii
ABSTRACT iii
FIGURE CAPTION ix
TABLE CAPTION xvii
LIST OF SYMBOLES xviii
CHAPTER 1 INTRODUCTION 1
1.1 BACKGROUND 1
1.2 EXHALED BREATH VOCs 7
1.3 VOCs GAS SENSOR 10
1.3.1 TRANSISTOR-BASED GAS SENSOR 13
1.3.2 SCHOTTKY DIODE BASED GAS SENSOR 16
1.3.3 RESISTIVE GAS SENSOR 18
1.4 SELECTIVITY of GAS SENSOR 21
1.4.1 TEMPERATURE MODULATION 22
1.4.2 GAS SENSOR ARRAY 23
1.4.3 SELECTIVITY BY USING FILTER 23
1.4.4 SYNTHESIS of NEW MATERIAL 26
1.4.5 DESIGN of NEW SENSOR CONSTRUCTION 26
1.5 SURFACE PROPERTIES of InN 26
1.5.1. ELECTRONIC PROPERTIES 26
1.6 OBJECTIVE 29
CHAPTER 2 SENSOR DESIGN, FABRICATION AND CHARACTERIZATIONS 31
2.1 InN SENSOR DESIGN 31
2.2 GROWTH of THE InN EPILAYER 34
2.3 SENSOR FABRICATION 37
2.3.1 SENSING DEVICE FABRICATION 37
2.3.2 HEATER FABRICATION 39
2.3.3 ASSEMBLY AND BONDING 41
2.4 MEASUREMENT SETUP AND METHODOLOGY 43
2.4.1 MEASUREMENT SETUP 43
2.5 GAS SAMPLING METHOD 46
2.5.1 GAS SAMPLING of ACETONE 46
2.5.2 GAS SAMPLING of AMMONIA 47
2.5.3 ABSORPTION SETUP of ACETONE 48
2.5.4 ABSORPTION SETUP of AMMONIA 49
2.6 ANALYTICAL INSTRUMENT 50
2.6.1 SELECTIVE ION FLOW TUBE MASS SPECTROSCOPY 50
2.6.2 GC-ATD-MS 52
2.6.3 WORKING PRINCIPLE of GC-ATD-MS 54
2.6.4 PEAK AREA VS. CONCENTRATION MODEL 56
2.6.5 T201 NH3 ANALYZER 58
2.6.6 SENSING MECHANISM of T201 NH3 ANALYZER 60
2.6.7 CHEMILUMINESCENCE CREATION IN THE REACTION CELL 61
2.6.8 THE PHOTOMULTIPLIER TUBE (PMT) 63
2.7 MEASUREMENT METHODOLOGY 67
CHAPTER 3 EXPERIMENTAL RESULT AND DISCUSSION 68
3.1 ABSORPTION ANALYSIS of 0.7 PPM ACETONE GAS BY GC-MSD 68
3.1.1 PEAK HEIGHT RESPONSE FOR THE 0.7 PPM ACETONE GAS 68
3.1.2 ANALYSIS of PEAK HEIGHT RESPONSE FOR THE 0.7 PPM ACETONE GAS IN WITH A FLOW RATE of 50 ML/MIN THROUGH THE 10 CC of SILICONE OIL BY GC-MSD 69
3.1.3 PEAK AREA RESPONSE VS. CONCENTRATION RESPONSE 71
3.1.4 ANALYSIS of 0.7 PPM ACETONE GAS IN 10 CC SILICONE OIL WITH A FLOW RATE of 20 ML/MIN BY SIFT-MS 71
3.1.5 ANALYSIS of 0.7 PPM ACETONE GAS IN 10 CC SILICONE OIL WITH A FLOW RATE of 10 CC/MIN BY USING SIFT-MS 73
3.1.6 ANALYSIS of 0.7 PPM ACETONE GAS IN 15 CC SILICONE OIL WITH A FLOW RATE of 10 ML/MIN BY SIFT-MS 75
3.1.7 ABSORPTION of ACETONE VS. GAS FLOW RATE 76
3.1.8 OUTPUT CONCENTRATION OF ACETONE GAS VS. ABSORPTION OF ACETONE GAS (%) IN SILICONE OIL. 78
3.2 ABSORPTION of ACETONE IN 100 CS SILICONE OIL 79
3.2.1 STANDARD CALIBRATION 79
3.2.2 ABSORPTION IN 100 CS SILICONE OIL WITH 50 CC/MIN 81
3.2.3 ABSORPTION IN 100 CS SILICONE OIL WITH 500 CC/MIN 82
3.2.4 ABSORPTION VS. FLOW RATE 83
3.3 ABSORPTION OF ACETONE IN 20 CS SILICONE OIL 84
3.3.1 STANDARD CALIBRATION 84
3.3.2 PEAK AREA RESPONSE of 0.7 PPM STANDARD ACETONE 85
3.3.3 ABSORPTION WITH 20 CC/MIN 86
3.3.4 ABSORPTION WITH 50 CC/MIN 87
3.3.5 ABSORPTION VS. FLOW RATE 88
3.4 ABSORPTION of AMMONIA IN SILICONE OIL 90
3.4.1 STANDARD AMMONIA TEST BY T201 AMMONIA ANALYZER 90
3.4.2 ABSORPTION of AMMONIA IN 500 CS SILICONE OIL 91
3.4.3 ABSORPTION of AMMONIA IN 100 CS SILICONE OIL 92
3.4.4 ABSORPTION of AMMONIA 20 CS SILICONE OIL 93
3.4.5 ABSORPTION VS. VISCOSITY 95
3.4.6 ABSORPTION MECHANISM IN SILICONE OIL 96
3.5 ULTRATHIN InN GAS SENSOR TEST 104
3.5.1 InN RESPONSE IN THE BIG CHAMBER 104
3.5.2 SENSING MECHANISM 106
3.5.3 THE DETECTION LIMIT of THE InN GAS SENSOR 108
3.5.4 TEMPERATURE EFFECT ON SENSITIVITY AND RESPONSE TIME of InN GAS SENSOR 109
3.5.5 CURRENT VARIATION RESPONSE FOR AMMONIA GAS 110
3.5.6 MINIATURIZED GAS CHAMBER SYSTEM 112
3.5.7 InN RESPONSE ON SMALL CHAMBER 114
3.5.8 InN RESPONSE THROUGH SILICONE OIL 115
CHAPTER 4 EXHALED BREATH ANALYSIS TEST 126
4.1 EXHALED BREATH ANALYSIS 126
4.1.1 EXHALED BREATH AMMONIA DETECTION BY T201 NH3 ANALYZER 129
4.1.2 BREATH TEST BY 1-LITER BAG 130
4.1.3 BREATH TEST BY 2-LITER BAG 132
4.1.4 EXHALED BREATH AMMONIA SAMPLING 134
4.1.5 RESULTS AND DISCUSSION 135
4.1.6 BREATH NH3 VS. BLOOD NH3 136
4.2 EXHALED BREATH SAMPLING FOR INTERFERENTS VOCS 136
4.2.1 EXHALED BREATH INTERFERENTS QUANTIFICATION BY GC-ATD-MS 138
CHAPTER 5 CONCLUSION 148
6.1 EXHALED BREATH BIOMARKERS TO DISTINGUISH THE LIVER MALFUNCTION 152
6.2 EXHALED BREATH BIOMARKER DETECTION BY THE SENSOR ARRAY 153
6.3 PORTABLE BREATH SENSOR 154
6.4 BREATH TEST FOR LIVER MALFUNCTION 154
6.5 HUMIDITY EFFECT 155
6.6 EFFECT of CARBON DIOXIDE 155
REFERENCE 156

REFERENCE

[1] A. A. Mokdad, A. D. Lopez, S. Shahraz, R. Lozano, A. H. Mokdad, J. Stanaway, et al., "Liver cirrhosis mortality in 187 countries between 1980 and 2010: a systematic analysis," BMC medicine, vol. 12, p. 145, 2014.
[2] G. Neri, "First Fifty Years of Chemoresistive Gas Sensors," Chemosensors, vol. 3, pp. 1-20, 2015.
[3] R. Capuano, M. Santonico, G. Pennazza, S. Ghezzi, E. Martinelli, C. Roscioni, et al., "The lung cancer breath signature: a comparative analysis of exhaled breath and air sampled from inside the lungs," Scientific reports, vol. 5, p. 16491, 2015.
[4] B. de Lacy Costello, A. Amann, H. Al-Kateb, C. Flynn, W. Filipiak, T. Khalid, et al., "A review of the volatiles from the healthy human body," Journal of breath research, vol. 8, p. 014001, 2014.
[5] J. Pereira, P. Porto-Figueira, C. Cavaco, K. Taunk, S. Rapole, R. Dhakne, et al., "Breath analysis as a potential and non-invasive frontier in disease diagnosis: an overview," Metabolites, vol. 5, pp. 3-55, 2015.
[6] A. D. Wilson, "Advances in electronic-nose technologies for the detection of volatile biomarker metabolites in the human breath," Metabolites, vol. 5, pp. 140-163, 2015.
[7] A. Manolis, "The diagnostic potential of breath analysis," Clinical chemistry, vol. 29, pp. 5-15, 1983.
[8] C. Wang and P. Sahay, "Breath analysis using laser spectroscopic techniques: breath biomarkers, spectral fingerprints, and detection limits," Sensors, vol. 9, pp. 8230-8262, 2009.
[9] Q. T. Zhang, P. Wang, J. P. Li, and X. G. Gao, "Diagnosis of diabetes by image detection of breath using gas-sensitive laps," Biosensors & Bioelectronics, vol. 15, pp. 249-256, Aug 2000.
[10] R. Xing, L. Xu, J. Song, C. Zhou, Q. Li, D. Liu, et al., "Preparation and Gas Sensing Properties of In2O3/Au Nanorods for Detection of Volatile Organic Compounds in Exhaled Breath," Scientific reports, vol. 5, 2015.
[11] W. Liu, L. Xu, K. Sheng, X. Zhou, B. Dong, G. Lu, et al., "A highly sensitive and moisture-resistant gas sensor for diabetes diagnosis with Pt@ In 2 O 3 nanowires and a molecular sieve for protection," NPG Asia Materials, p. 1, 2018.
[12] M. ul Haq, Z. Wen, Z. Zhang, S. Khan, Z. Lou, Z. Ye, et al., "A two-step synthesis of nanosheet-covered fibers based on α-Fe 2 O 3/NiO composites towards enhanced acetone sensing," Scientific reports, vol. 8, p. 1705, 2018.
[13] H.-J. Choi, S.-J. Choi, S. Choo, I.-D. Kim, and H. Lee, "Hierarchical ZnO Nanowires-loaded Sb-doped SnO 2-ZnO Micrograting Pattern via Direct Imprinting-assisted Hydrothermal Growth and Its Selective Detection of Acetone Molecules," Scientific reports, vol. 6, p. 18731, 2016.
[14] Y. Zhang, J. Zhao, T. Du, Z. Zhu, J. Zhang, and Q. Liu, "A gas sensor array for the simultaneous detection of multiple VOCs," Scientific Reports, vol. 7, p. 1960, 2017.
[15] S. Tjoa and P. Fennessey, "The Identification of Trimethylamine Excess in Man - Quantitative-Analysis and Biochemical-Origins," Analytical Biochemistry, vol. 197, pp. 77-82, Aug 15 1991.
[16] K. T. Moorhead, D. Lee, J. G. Chase, A. Moot, K. Ledingham, J. Scotter, et al., "Classifying algorithms for SIFT-MS technology and medical diagnosis," Computer methods and programs in biomedicine, vol. 89, pp. 226-238, 2008.
[17] O. Tsuboi, S. Momose, and R. Takasu, "Mobile Sensor that Quickly and Selectively Measures Ammonia Gas Components in Breath," FUJITSU Sci. Tech. J, vol. 53, pp. 38-43, 2017.
[18] P. Gouma, K. Kalyanasundaram, X. Yun, M. Stanacevic, and L. Wang, "Nanosensor and breath analyzer for ammonia detection in exhaled human breath," IEEE Sensors Journal, vol. 10, pp. 49-53, 2010.
[19] L. A. Spacek, A. Strzepka, S. Saha, J. Kotula, J. Gelb, S. Guilmain, et al., "Repeated Measures of Blood and Breath Ammonia in Response to Control, Moderate and High Protein Dose in Healthy Men," Scientific reports, vol. 8, p. 2554, 2018.
[20] C. Shimamoto, I. Hirata, and K. Katsu, "Breath and blood ammonia in liver cirrhosis," Hepato-gastroenterology, vol. 47, pp. 443-445, 2000.
[21] S. Chen, V. Mahadevan, and L. Zieve, "Volatile fatty acids in the breath of patients with cirrhosis of the liver," The Journal of laboratory and clinical medicine, vol. 75, pp. 622-627, 1970.
[22] A. Tangerman, M. Meuwese-Arends, and J. M. Jansen, "Cause and composition of foetor hepaticus," The Lancet, vol. 343, p. 483, 1994.
[23] K. Hiroshi, H. Masaya, S. Nariyoshi, and M. Makoto, "Evaluation of volatile sulfur compounds in the expired alveolar gas in patients with liver cirrhosis," Clinica Chimica Acta, vol. 85, pp. 279-284, 1978.
[24] J. van den Broek, A. T. Güntner, and S. E. Pratsinis, "Highly Selective and Rapid Breath Isoprene Sensing Enabled by Activated Alumina Filter," ACS sensors, vol. 3, pp. 677-683, 2018.
[25] A. M. Diskin, P. Španěl, and D. Smith, "Time variation of ammonia, acetone, isoprene and ethanol in breath: a quantitative SIFT-MS study over 30 days," Physiological measurement, vol. 24, p. 107, 2003.
[26] H. Hao, M. Chiang, S. Liu, C. Hsiao, C. Yang, K. Tang, et al., "IMPROVED SURFACE ACOUSTIC WAVE SENSOR FOR LOW CONCENTRATION AMMONIA/METHANE MIXTURE GASES DETECTION."
[27] P. Španěl, S. Davies, and D. Smith, "Quantification of breath isoprene using the selected ion flow tube mass spectrometric analytical method," Rapid communications in mass spectrometry, vol. 13, pp. 1733-1738, 1999.
[28] N. Nelson, V. Lagesson, A. R. Nosratabadi, J. Ludvigsson, and C. Tagesson, "Exhaled isoprene and acetone in newborn infants and in children with diabetes mellitus," Pediatric research, vol. 44, p. 363, 1998.
[29] S. Van den Velde, F. Nevens, D. van Steenberghe, and M. Quirynen, "GC–MS analysis of breath odor compounds in liver patients," Journal of Chromatography B, vol. 875, pp. 344-348, 2008.
[30] G. D. Wedlake and D. B. Robinson, "Solubility of Carbon dioxide in silicone Oil," Journal of Chemical and Engineering Data, vol. 24, pp. 305-306, 1979.
[31] T. K. Poddar, "Removal of VOCs from air by absorption and stripping in hollow fiber devices," New Jersey Institute of Technology, Department of Chemical Engineering, Chemistry and Environmental Sciemce, 1995.
[32] T. Elperin and A. Fominykh, "Model of gas absorption in gas-liquid plug flow with first-order and zero-order chemical reaction," Heat and mass transfer, vol. 39, pp. 195-199, 2003.
[33] T. Elperin and A. Fominykh, "Mass transfer during gas absorption in a vertical gas-liquid slug flow with small bubbles in liquid plugs," Heat and mass transfer, vol. 33, pp. 489-494, 1998.
[34] R. Fernandes, R. Semiat, and A. Dukler, "Hydrodynamic model for gas‐liquid slug flow in vertical tubes," AIChE Journal, vol. 29, pp. 981-989, 1983.
[35] M. Righettoni, A. Amann, and S. E. Pratsinis, "Breath analysis by nanostructured metal oxides as chemo-resistive gas sensors," Materials Today, vol. 18, pp. 163-171, 2015.
[36] A. Amann, M. Corradi, P. Mazzone, and A. Mutti, "Lung cancer biomarkers in exhaled breath," 2011.
[37] H. Haick, Y. Y. Broza, P. Mochalski, V. Ruzsanyi, and A. Amann, "Assessment, origin, and implementation of breath volatile cancer markers," Chemical Society Reviews, vol. 43, pp. 1423-1449, 2014.
[38] M. M. Adeva, G. Souto, N. Blanco, and C. Donapetry, "Ammonium metabolism in humans," Metabolism-Clinical and Experimental, vol. 61, pp. 1495-1511, 2012.
[39] G. Neri, A. Lacquaniti, G. Rizzo, N. Donato, M. Latino, and M. Buemi, "Real-time monitoring of breath ammonia during haemodialysis: use of ion mobility spectrometry (IMS) and cavity ring-down spectroscopy (CRDS) techniques," Nephrology Dialysis Transplantation, vol. 27, pp. 2945-2952, 2012.
[40] V. Gutiérrez-de-Juan, S. L. de Davalillo, D. Fernández-Ramos, L. Barbier-Torres, I. Zubiete-Franco, P. Fernández-Tussy, et al., "A morphological method for ammonia detection in liver," PloS one, vol. 12, p. e0173914, 2017.
[41] J. C. Anderson, W. J. Lamm, and M. P. Hlastala, "Measuring airway exchange of endogenous acetone using a single-exhalation breathing maneuver," Journal of Applied Physiology, vol. 100, pp. 880-889, 2006.
[42] J. King, K. Unterkofler, G. Teschl, S. Teschl, H. Koc, H. Hinterhuber, et al., "A mathematical model for breath gas analysis of volatile organic compounds with special emphasis on acetone," Journal of mathematical biology, vol. 63, pp. 959-999, 2011.
[43] J. D. Pleil and A. B. Lindstrom, "Exhaled human breath measurement method for assessing exposure to halogenated volatile organic compounds," Clinical chemistry, vol. 43, pp. 723-730, 1997.
[44] C. Deng, J. Zhang, X. Yu, W. Zhang, and X. Zhang, "Determination of acetone in human breath by gas chromatography–mass spectrometry and solid-phase microextraction with on-fiber derivatization," Journal of Chromatography B, vol. 810, pp. 269-275, 2004.
[45] J. King, A. Kupferthaler, B. Frauscher, H. Hackner, K. Unterkofler, G. Teschl, et al., "Measurement of endogenous acetone and isoprene in exhaled breath during sleep," Physiological measurement, vol. 33, p. 413, 2012.
[46] M. Statheropoulos, A. Agapiou, and A. Georgiadou, "Analysis of expired air of fasting male monks at Mount Athos," Journal of Chromatography B, vol. 832, pp. 274-279, 2006.
[47] C. Turner, P. Španěl, and D. Smith, "A longitudinal study of ammonia, acetone and propanol in the exhaled breath of 30 subjects using selected ion flow tube mass spectrometry, SIFT-MS," Physiological Measurement, vol. 27, p. 321, 2006.
[48] S. Davies, P. Spanel, and D. Smith, "Quantitative analysis of ammonia on the breath of patients in end-stage renal failure," Kidney international, vol. 52, pp. 223-228, 1997.
[49] D. J. Kearney, T. Hubbard, and D. Putnam, "Breath ammonia measurement in Helicobacter pylori infection," Digestive diseases and sciences, vol. 47, pp. 2523-2530, 2002.
[50] B. Grabowska-Polanowska, J. Faber, M. Skowron, P. Miarka, A. Pietrzycka, I. Śliwka, et al., "Detection of potential chronic kidney disease markers in breath using gas chromatography with mass-spectral detection coupled with thermal desorption method," Journal of chromatography A, vol. 1301, pp. 179-189, 2013.
[51] A. Tangerman, M. T. Meuwese-Arends, and J. H. van Tongeren, "A new sensitive assay for measuring volatile sulphur compounds in human breath by Tenax trapping and gas chromatography and its application in liver cirrhosis," Clinica Chimica Acta, vol. 130, pp. 103-110, 1983.
[52] W. Filipiak, A. Sponring, M. M. Baur, C. Ager, A. Filipiak, H. Wiesenhofer, et al., "Characterization of volatile metabolites taken up by or released from Streptococcus pneumoniae and Haemophilus influenzae by using GC-MS," Microbiology, vol. 158, pp. 3044-3053, 2012.
[53] S. A. Kharitonov and P. J. Barnes, "Biomarkers of some pulmonary diseases in exhaled breath," Biomarkers, vol. 7, pp. 1-32, 2002.
[54] K. Zayasu, K. Sekizawa, S. Okinaga, M. Yamaya, T. Ohrui, and H. Sasaki, "Increased carbon monoxide in exhaled air of asthmatic patients," American Journal of Respiratory and Critical Care Medicine, vol. 156, pp. 1140-1143, 1997.
[55] K. Stamyr, O. Vaittinen, J. Jaakola, J. Guss, M. Metsälä, G. Johanson, et al., "Background levels of hydrogen cyanide in human breath measured by infrared cavity ring down spectroscopy," Biomarkers, vol. 14, pp. 285-291, 2009.
[56] C.-C. Wang, Y.-C. Weng, and T.-C. Chou, "Acetone sensor using lead foil as working electrode," Sensors and Actuators B: Chemical, vol. 122, pp. 591-595, 2007.
[57] M. Penza, G. Cassano, A. Sergi, C. L. Sterzo, and M. Russo, "SAW chemical sensing using poly-ynes and organometallic polymer films," Sensors and Actuators B: Chemical, vol. 81, pp. 88-98, 2001.
[58] D. J. Young, İ. E. Pehlivanoğlu, and C. A. Zorman, "Silicon carbide MEMS-resonator-based oscillator," Journal of Micromechanics and Microengineering, vol. 19, p. 115027, 2009.
[59] W. Kwok, Y. Bow, W. Chan, M. Poon, P. Wan, and H. Wong, "Study of porous silicon gas sensor," in Electron Devices Meeting, 1999. Proceedings. 1999 IEEE Hong Kong, 1999, pp. 80-83.
[60] J. Li, Y. Lu, Q. Ye, M. Cinke, J. Han, and M. Meyyappan, "Carbon nanotube sensors for gas and organic vapor detection," Nano Letters, vol. 3, pp. 929-933, 2003.
[61] A. Vomiero, S. Bianchi, E. Comini, G. Faglia, M. Ferroni, and G. Sberveglieri, "Controlled growth and sensing properties of In2O3 nanowires," Crystal Growth and Design, vol. 7, pp. 2500-2504, 2007.
[62] L. Wang, A. Teleki, S. Pratsinis, and P. Gouma, "Ferroelectric WO3 nanoparticles for acetone selective detection," Chemistry of Materials, vol. 20, pp. 4794-4796, 2008.
[63] D.-S. Lee, J.-H. Lee, Y.-H. Lee, and D.-D. Lee, "GaN thin films as gas sensors," Sensors and Actuators B: Chemical, vol. 89, pp. 305-310, 2003.
[64] J. Schalwig, G. Müller, M. Eickhoff, O. Ambacher, and M. Stutzmann, "Gas sensitive GaN/AlGaN-heterostructures," Sensors and Actuators B: Chemical, vol. 87, pp. 425-430, 2002.
[65] C. Wu, C. Shen, H. Lin, H. Lee, and S. Gwo, "Direct evidence of 8: 9 commensurate heterojunction formed between InN and AlN on c plane," Applied Physics Letters, vol. 87, p. 241916, 2005.
[66] Y.-S. Lu, C.-C. Huang, J. A. Yeh, C.-F. Chen, and S. Gwo, "InN-based anion selective sensors in aqueous solutions," Applied Physics Letters, vol. 91, p. 202109, 2007.
[67] Y.-H. Chang, Y.-S. Lu, Y.-L. Hong, C.-T. Kuo, S. Gwo, and J. A. Yeh, "Effects of (NH4) 2Sx treatment on indium nitride surfaces," Journal of Applied Physics, vol. 107, p. 043710, 2010.
[68] Y.-S. Lu, C.-L. Ho, J. A. Yeh, H.-W. Lin, and S. Gwo, "Anion detection using ultrathin InN ion selective field effect transistors," Applied Physics Letters, vol. 92, p. 2102, 2008.
[69] Y.-H. Chang, K.-K. Chang, S. Gwo, and J. A. Yeh, "Highly sensitive hydrogen detection using a Pt-catalyzed InN epilayer," Applied Physics Express, vol. 3, p. 114101, 2010.
[70] Y.-H. Chang, Y.-S. Lu, Y.-L. Hong, S. Gwo, and J. A. Yeh, "Highly sensitive pH sensing using an indium nitride ion-sensitive field-effect transistor," Sensors Journal, IEEE, vol. 11, pp. 1157-1161, 2011.
[71] Y.-S. Lin and J. A. Yeh, "GaN-based light-emitting diodes grown on nanoscale patterned sapphire substrates with void-embedded cortex-like nanostructures," Applied physics express, vol. 4, p. 092103, 2011.
[72] I. Lundström, S. Shivaraman, C. Svensson, and L. Lundkvist, "A hydrogen− sensitive MOS field− effect transistor," Applied Physics Letters, vol. 26, pp. 55-57, 1975.
[73] B. Kang, R. Mehandru, S. Kim, F. Ren, R. Fitch, J. Gillespie, et al., "Hydrogen-induced reversible changes in drain current in Sc2O3/AlGaN/GaN high electron mobility transistors," Applied physics letters, vol. 84, p. 4635, 2004.
[74] X. Wang, X. Wang, C. Feng, C. Yang, B. Wang, J. Ran, et al., "Hydrogen sensors based on AlGaN/AlN/GaN HEMT," Microelectronics Journal, vol. 39, pp. 20-23, 2008.
[75] L. Tongson, B. Knox, T. Sullivan, and S. Fonash, "Comparative study of chemical and polarization characteristics of Pd/Si and Pd/SiOx/Si Schottky‐barrier‐type devices," Journal of Applied Physics, vol. 50, pp. 1535-1537, 1979.
[76] A. Saaman and P. Bergveld, "A classification of chemically sensitive semiconductor devices," Sensors and Actuators, vol. 7, pp. 75-87, 1985.
[77] M. Shivaraman, I. Lundström, C. Svensson, and H. Hammarsten, "Hydrogen sensitivity of palladium–thin-oxide–silicon schottky barriers," Electronics Letters, vol. 12, pp. 483-484, 1976.
[78] P. F. Ruths, S. Ashok, S. J. Fonash, and J. M. Rut, "A study of Pd/Si MIS Schottky barrier diode hydrogen detector," Electron Devices, IEEE Transactions on, vol. 28, pp. 1003-1009, 1981.
[79] B. Keramati and J. Zemel, "Confirmation of hydrogen surface states at the Si SiO2 interface," in Proc. Int. Topics Conf. Physics of SiO2 and its Interfaces, 1978, pp. 459-463.
[80] B. Luther, S. Wolter, and S. Mohney, "High temperature Pt Schottky diode gas sensors on n-type GaN," Sensors and Actuators B: Chemical, vol. 56, pp. 164-168, 1999.
[81] Y.-L. Wang, B. Chu, C. Chang, K. Chen, Y. Zhang, Q. Sun, et al., "Hydrogen sensing of N-polar and Ga-polar GaN Schottky diodes," Sensors and Actuators B: Chemical, vol. 142, pp. 175-178, 2009.
[82] J. Northrup and J. Neugebauer, "Strong affinity of hydrogen for the GaN (000-1) surface: Implications for molecular beam epitaxy and metalorganic chemical vapor deposition," Applied physics letters, vol. 85, 2004.
[83] M. Mayumi, F. Satoh, Y. Kumagai, K. Takemoto, and A. Koukitu, "Influence of polarity on surface reaction between GaN {0001} and hydrogen," physica status solidi (b), vol. 228, pp. 537-541, 2001.
[84] A. Teleki, S. Pratsinis, K. Kalyanasundaram, and P. Gouma, "Sensing of organic vapors by flame-made TiO 2 nanoparticles," Sensors and Actuators B: Chemical, vol. 119, pp. 683-690, 2006.
[85] P. Murade, V. Sangawar, G. Chaudhari, V. Kapse, and A. Bajpeyee, "Acetone gas-sensing performance of Sr-doped nanostructured LaFeO 3 semiconductor prepared by citrate sol–gel route," Current Applied Physics, vol. 11, pp. 451-456, 2011.
[86] N. Kakati, S. H. Jee, S. H. Kim, J. Y. Oh, and Y. S. Yoon, "Thickness dependency of sol-gel derived ZnO thin films on gas sensing behaviors," Thin Solid Films, vol. 519, pp. 494-498, 2010.
[87] H. Ahn, Y. Wang, S. H. Jee, M. Park, Y. S. Yoon, and D.-J. Kim, "Enhanced UV activation of electrochemically doped Ni in ZnO nanorods for room temperature acetone sensing," Chemical Physics Letters, vol. 511, pp. 331-335, 2011.
[88] I. Ray and A. Sen, "Shirshendu Chakraborty1, Dibyajyoti Banerjee2," Current science, vol. 94, p. 237, 2008.
[89] Y. Masuda, T. Itoh, W. Shin, and K. Kato, "SnO2 Nanosheet/Nanoparticle Detector for the Sensing of 1-Nonanal Gas Produced by Lung Cancer," Scientific reports, vol. 5, 2015.
[90] N. M. Vuong, D. Kim, and H. Kim, "Porous Au-embedded WO3 Nanowire Structure for Efficient Detection of CH4 and H2S," Scientific reports, vol. 5, 2015.
[91] G. Dong, H. Fan, H. Tian, J. Fang, and Q. Li, "Gas-sensing and electrical properties of perovskite structure p-type barium-substituted bismuth ferrite," RSC Advances, vol. 5, pp. 29618-29623, 2015.
[92] G. Halek, M. Malewicz, and H. Teterycz, "Methods of selectivity improvements of semiconductor gas sensors," in Students and Young Scientists Workshop" Photonics and Microsystems", 2009 International, 2009, pp. 31-35.
[93] D. C. Meier, B. Raman, and S. Semancik, "Detecting Chemical Hazards with Temperature-Programmed Microsensors: Overcoming Complex Analytical Problems with Multidimensional Databases*," Analytical Chemistry, vol. 2, 2009.
[94] A. P. Lee and B. J. Reedy, "Temperature modulation in semiconductor gas sensing," Sensors and Actuators B: Chemical, vol. 60, pp. 35-42, 1999.
[95] A. Bermak, S. B. Belhouari, M. Shi, and D. Martinez, "Pattern recognition techniques for odor discrimination in gas sensor array," Encyclopedia of Sensors, vol. 10, pp. 1-17, 2006.
[96] E. Kim, S. Lee, J. H. Kim, C. Kim, Y. T. Byun, H. S. Kim, et al., "Pattern Recognition for Selective Odor Detection with Gas Sensor Arrays," Sensors, vol. 12, pp. 16262-16273, 2012.
[97] M. Schweizer-Berberich, S. Strathmann, U. Weimar, R. Sharma, A. Seube, A. Peyre-Lavigne, et al., "Strategies to avoid VOC cross-sensitivity of SnO 2-based CO sensors," Sensors and Actuators B: Chemical, vol. 58, pp. 318-324, 1999.
[98] M. Vilaseca, J. Coronas, A. Cirera, A. Cornet, J. R. Morante, and J. Santamaria, "Gas detection with SnO 2 sensors modified by zeolite films," Sensors and Actuators B: Chemical, vol. 124, pp. 99-110, 2007.
[99] T. K. Poddar, Removal of VOCs from air by absorption and stripping in hollow fiber devices, 1995.
[100] W. Göpel and K. D. Schierbaum, "SnO 2 sensors: current status and future prospects," Sensors and Actuators B: Chemical, vol. 26, pp. 1-12, 1995.
[101] O. Safonova, M. Rumyantseva, L. Ryabova, M. Labeau, G. Delabouglise, and A. Gaskov, "Effect of combined Pd and Cu doping on microstructure, electrical and gas sensor properties of nanocrystalline tin dioxide," Materials Science and Engineering: B, vol. 85, pp. 43-49, 2001.
[102] A. G. Bhuiyan, A. Hashimoto, and A. Yamamoto, "Indium nitride (InN): A review on growth, characterization, and properties," Journal of Applied Physics, vol. 94, pp. 2779-2808, 2003.
[103] H. Lu, W. J. Schaff, L. F. Eastman, and C. Stutz, "Surface charge accumulation of InN films grown by molecular-beam epitaxy," Applied physics letters, vol. 82, pp. 1736-1738, 2003.
[104] K. A. Rickert, A. B. Ellis, F. J. Himpsel, H. Lu, W. Schaff, J. M. Redwing, et al., "X-ray photoemission spectroscopic investigation of surface treatments, metal deposition, and electron accumulation on InN," Applied physics letters, vol. 82, pp. 3254-3256, 2003.
[105] T. Veal, I. Mahboob, L. Piper, C. McConville, H. Lu, and W. Schaff, "Indium nitride: Evidence of electron accumulation," Journal of Vacuum Science & Technology B, vol. 22, pp. 2175-2178, 2004.
[106] I. Mahboob, T. Veal, L. Piper, C. McConville, H. Lu, W. Schaff, et al., "Origin of electron accumulation at wurtzite InN surfaces," Physical Review B, vol. 69, p. 201307, 2004.
[107] I. Mahboob, T. Veal, C. McConville, H. Lu, and W. Schaff, "Intrinsic electron accumulation at clean InN surfaces," Physical review letters, vol. 92, p. 036804, 2004.
[108] C.-L. Wu, H.-M. Lee, C.-T. Kuo, C.-H. Chen, and S. Gwo, "Absence of Fermi-level pinning at cleaved nonpolar InN surfaces," Physical review letters, vol. 101, p. 106803, 2008.
[109] M. Wu, S. Zhou, A. Vantomme, Y. Huang, H. Wang, and H. Yang, "High-precision determination of lattice constants and structural characterization of InN thin films," 2006.
[110] M. Wu, S. Zhou, A. Vantomme, Y. Huang, H. Wang, and H. Yang, "High-precision determination of lattice constants and structural characterization of InN thin films," Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, vol. 24, pp. 275-279, 2006.
[111] V.-T. Rangel-Kuoppa, S. Suihkonen, M. Sopanen, and H. Lipsanen, "Metal contacts on InN: Proposal for Schottky contact," Japanese journal of applied physics, vol. 45, p. 36, 2006.
[112] E. Souteynard, D. Nicolas, and J. Martin, "Semiconductor/metal/gas behaviour through surface-potential change," Sensors and Actuators B: Chemical, vol. 25, pp. 871-875, 1995.
[113] G. J. Francis, V. S. Langford, D. B. Milligan, and M. J. McEwan, "Real-time monitoring of hazardous air pollutants," Analytical chemistry, vol. 81, pp. 1595-1599, 2009.
[114] Z. Xue, L.-X. Duan, and X. Qi, "Gas Chromatography Mass Spectrometry Coupling Techniques," in Plant Metabolomics, ed: Springer, 2015, pp. 25-44.
[115] L.-R. Snyder, "A rapid approach to selecting the best experimental conditions for high-speed liquid column chromatography. Part I—estimating initial sample resolution and the final resolution required by a given problem," Journal of Chromatographic Science, vol. 10, pp. 200-212, 1972.
[116] Y. B. Fernández, E. Cartmell, A. Soares, E. McAdam, P. Vale, C. Darche-Dugaret, et al., "Gas to liquid mass transfer in rheologically complex fluids," Chemical Engineering Journal, vol. 273, pp. 656-667, 2015.
[117] B. Özbek and S. Gayik, "The studies on the oxygen mass transfer coefficient in a bioreactor," Process Biochemistry, vol. 36, pp. 729-741, 2001.
[118] P. Snabre and F. Magnifotcham, "I. Formation and rise of a bubble stream in a viscous liquid," The European Physical Journal B-Condensed Matter and Complex Systems, vol. 4, pp. 369-377, 1998.
[119] R. Kumar and N. Kuloor, "The formation of bubbles and drops," Advances in chemical engineering, vol. 8, pp. 255-368, 1970.
[120] A. K. Ghosh and J. Ulbrecht, "Bubble formation from a sparger in polymer solutions—II. Moving liquid," Chemical engineering science, vol. 44, pp. 969-977, 1989.
[121] L. Milne-Thomson, "A general solution of the equations of hydrodynamics," Journal of Fluid Mechanics, vol. 2, pp. 88-88, 1957.
[122] A. Wraith, "Two stage bubble growth at a submerged plate orifice," Chemical Engineering Science, vol. 26, pp. 1659-1671, 1971.
[123] J. Davidson, "Bubble formation at an orifice in an inviscid liquid," Transactions of the Institution of Chemical Engineers, vol. 38, pp. 335-342, 1960.
[124] S. Golunski, "Why use platinum in catalytic converters?," Tc, vol. 975, p. 44, 2007.
[125] S. M. Abbott, J. B. Elder, P. Španěl, and D. Smith, "Quantification of acetonitrile in exhaled breath and urinary headspace using selected ion flow tube mass spectrometry," International Journal of Mass Spectrometry, vol. 228, pp. 655-665, 2003.
[126] C.-C. Cheng, Y.-Y. Tsai, K.-W. Lin, H.-I. Chen, W.-H. Hsu, C.-W. Hong, et al., "Study of hydrogen-sensing characteristics of a Pt-oxide-AlGaAs metal-oxide-semiconductor high electron mobility transistor," Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena, vol. 23, pp. 1943-1947, 2005.
[127] N. Barsan and U. Weimar, "Conduction model of metal oxide gas sensors," Journal of Electroceramics, vol. 7, pp. 143-167, 2001.
[128] T.-Y. Chen, H.-I. Chen, Y.-J. Liu, C.-C. Huang, C.-S. Hsu, C.-F. Chang, et al., "Ammonia sensing properties of a Pt/AlGaN/GaN Schottky diode," IEEE Transactions on Electron Devices, vol. 58, pp. 1541-1547, 2011.
[129] K. Lundström, M. Shivaraman, and C. Svensson, "A hydrogen‐sensitive Pd‐gate MOS transistor," Journal of Applied Physics, vol. 46, pp. 3876-3881, 1975.
[130] I. Lundström, M. Shivaraman, and C. Svensson, "Chemical reactions on palladium surfaces studied with Pd-MOS structures," Surface science, vol. 64, pp. 497-519, 1977.
[131] J. Ding, T. J. McAvoy, R. E. Cavicchi, and S. Semancik, "Surface state trapping models for SnO 2-based microhotplate sensors," Sensors and Actuators B: Chemical, vol. 77, pp. 597-613, 2001.
[132] S.-C. Chang, "Oxygen chemisorption on tin oxide: correlation between electrical conductivity and EPR measurements," J. Vac. Sci. Technol, vol. 17, pp. 366-369, 1980.
[133] M. Che and A. Tench, "Characterization and Reactivity of Mononuclear Oxygen Species," Advances in Catalysis, vol. 31, p. 77, 1983.
[134] T.-Y. Chen, H.-I. Chen, Y.-J. Liu, C.-C. Huang, C.-S. Hsu, C.-F. Chang, et al., "Ammonia sensing characteristics of a Pt/AlGaN/GaN Schottky diode," Sensors and Actuators B: Chemical, vol. 155, pp. 347-350, 2011.
[135] S.-C. Wang and M. O. Shaikh, "A room temperature H2 sensor fabricated using high performance Pt-loaded SnO2 nanoparticles," Sensors, vol. 15, pp. 14286-14297, 2015.
[136] I. Lundström, "Hydrogen sensitive MOS-structures: part 1: principles and applications," Sensors and actuators, vol. 1, pp. 403-426, 1981.
[137] I. Lundström and D. Söderberg, "Hydrogen sensitive mos-structures part 2: characterization," Sensors and Actuators, vol. 2, pp. 105-138, 1981.
[138] F. Shao, M. W. Hoffmann, J. D. Prades, J. R. Morante, N. r. López, and F. Hernández-Ramírez, "Interaction mechanisms of ammonia and tin oxide: A combined analysis using single nanowire devices and DFT calculations," The Journal of Physical Chemistry C, vol. 117, pp. 3520-3526, 2013.
[139] L. Qin, J. Xu, X. Dong, Q. Pan, Z. Cheng, Q. Xiang, et al., "The template-free synthesis of square-shaped SnO2 nanowires: the temperature effect and acetone gas sensors," Nanotechnology, vol. 19, p. 185705, 2008.
[140] S.-J. Choi, B.-H. Jang, S.-J. Lee, B. K. Min, A. Rothschild, and I.-D. Kim, "Selective detection of acetone and hydrogen sulfide for the diagnosis of diabetes and halitosis using SnO2 nanofibers functionalized with reduced graphene oxide nanosheets," ACS applied materials & interfaces, vol. 6, pp. 2588-2597, 2014.
[141] S. Das, S. Ghosh, R. Kumar, A. Bag, and D. Biswas, "Highly Sensitive Acetone Sensor Based on Pd/AlGaN/GaN Resistive Device Grown by Plasma-Assisted Molecular Beam Epitaxy," IEEE Transactions on Electron Devices, vol. 64, pp. 4650-4656, 2017.
[142] G. Korotcenkov, V. Brinzari, J. R. Stetter, I. Blinov, and V. Blaja, "The nature of processes controlling the kinetics of indium oxide-based thin film gas sensor response," Sensors and Actuators B: Chemical, vol. 128, pp. 51-63, 2007.
[143] H. Yuzawa, T. Mori, H. Itoh, and H. Yoshida, "Reaction mechanism of ammonia decomposition to nitrogen and hydrogen over metal loaded titanium oxide photocatalyst," The Journal of Physical Chemistry C, vol. 116, pp. 4126-4136, 2012.
[144] N. Howlader, A. Noone, M. Krapcho, J. Garshell, D. Miller, S. Altekruse, et al., "SEER cancer statistics review, 1975–2011 [based on November 2013 SEER data submission]. Bethesda, MD: National Cancer Institute. 2014. Apr [accessed 2014 Oct 8]," seer. cancer. gov/csr, 2014.
[145] L. Blanchet, A. Smolinska, A. Baranska, E. Tigchelaar, M. Swertz, A. Zhernakova, et al., "Factors that influence the volatile organic compound content in human breath," Journal of breath research, vol. 11, p. 016013, 2017.
[146] R. Xing, L. Xu, J. Song, C. Zhou, Q. Li, D. Liu, et al., "Preparation and gas sensing properties of In 2 O 3/Au nanorods for detection of volatile organic compounds in exhaled breath," Scientific reports, vol. 5, p. 10717, 2015.