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Sokolovskij, R. (author), Zhang, Jian (author), Zheng, Hongze (author), Li, Wenmao (author), Jiang, Yang (author), Yang, Gaiying (author), Yu, Hongyu (author), Sarro, Pasqualina M (author), Zhang, Kouchi (author)The present work reports on the hydrogen gas detection properties of Pt-AlGaN/GaN high electron mobility transistor (HEMT) sensors with recessed gate structure. Devices with gate recess depths from 5 to 15 nm were fabricated using a precision cyclic etching method, examined with AFM, STEM and EDS, and tested towards H2 response at high...journal article 2020
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Sun, J. (author), Sokolovskij, R. (author), Iervolino, E. (author), Liu, Zewen (author), Sarro, Pasqualina M (author), Zhang, Kouchi (author)We developed an AlGaN/GaN high electron mobility transistor (HEMT) sensor with a tungsten trioxide (WO<sub>3</sub>) nano-film modified gate for nitrogen dioxide (NO<sub>2</sub>) detection. The device has a suspended circular membrane structure and an integrated micro-heater. The thermal characteristic of the Platinum (Pt) micro-heater and the...journal article 2019
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Zhang, Jian (author), Sokolovskij, R. (author), Chen, Ganhui (author), Zhu, Yumeng (author), Qi, Yongle (author), Lin, Xinpeng (author), Li, Wenmao (author), Zhang, G. (author), Jiang, Yu-Long (author), Yu, Hongyu (author)In this paper, a method to extend the detection range of hydrogen sulfide (H<sub>2</sub>S) gas sensor is demonstrated. The sensor is based on AlGaN/GaN high electron mobility transistors (HEMTs) with Pt gate. It is observed that the as-fabricated devices exhibited sensing signal saturation at 30 ppm H<sub>2</sub>S exposure in dry air. A pre...journal article 2019
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Sokolovskij, R. (author), Zhang, Jian (author), Iervolino, E. (author), Zhao, Changhui (author), Santagata, F. (author), Wang, F. (author), Yu, Hongyu (author), Sarro, Pasqualina M (author), Zhang, Kouchi (author)AlGaN/GaN high electron mobility transistor (HEMT)-based sensors with catalytic platinum gate were micro-fabricated on commercially available epitaxial wafers and extensively characterized for ppm level hydrogen sulfide (H<sub>2</sub>S) detection for industrial safety applications. High operating temperature above 150 °C enabled large signal...journal article 2018
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Sokolovskij, R. (author), Iervolino, E. (author), Zhao, Changhui (author), Wang, F. (author), Yu, Hongyu (author), Santagata, F. (author), Sarro, Pasqualina M (author), Zhang, Kouchi (author)This paper reports on the layout optimization of Pt-AlGaN/GaN HEMT-sensors for enhancing hydrogen sensor performance. Sensors with gate width and length ratios W<sub>g</sub>/L<sub>g</sub> from 0.25 to 10 were designed, fabricated and tested for the detection of hydrogen gas at 200 °C. Sensitivity, sensing current variation and transient...conference paper 2017
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Precision Recess of AlGaN/GaN with Controllable Etching Rate Using ICP-RIE Oxidation and Wet EtchingSokolovskij, R. (author), Sun, J. (author), Santagata, F. (author), Iervolino, E. (author), Li, S. (author), Zhang, G.Y. (author), Sarro, Pasqualina M (author), Zhang, Kouchi (author)A method for highly controllable etching of AlGaN/GaN for the fabrication of high sensitivity HEMT based sensors is developed. The process consists of cyclic oxidation of nitride with O<sub>2</sub> plasma using ICP-RIE etcher followed by wet etching of the oxidized layer. Previously reported cyclic oxidation-based GaN etching obtained very...journal article 2016