Ammonia Sensing Properties of a Pt/AlGaN/GaN Schottky Diode

作者：Chen Tai You^*; Chen Huey Ing; Liu Yi Jung; Huang Chien Chang; Hsu Chi Shiang; Chang Chung Fu; Liu Wen Chau

来源：IEEE Transactions on Electron Devices, 2011, 58(5): 1541-1547.

DOI：10.1109/TED.2011.2115245

• AlGaN
• ammonia
• Schottky diode
• sensor

An interesting Pt/AlGaN/GaN Schottky-type ammonia gas sensor is fabricated and studied. Both the steady-and transient-state behaviors of ammonia adsorption reactions are investigated. At 150 degrees C, significant ammonia detection is observed under a low ammonia concentration of 35-ppm NH3/air. Moreover, a high ammonia sensing response of 18 300% and the large Schottky barrier variation ratio Delta phi(b)/phi(b), air of 13.8% are observed upon exposure to a 1% NH3/air gas at 150 degrees C. The presence of dipoles at the metal-semiconductor interface leads to a lowering effect of Schottky barrier height and a larger current. In addition, based on thermodynamics, in contrast with a hydrogen adsorption reaction, the ammonia adsorption reaction is an endothermic reaction. Consequently, the studied NH3 sensor structure provides the promise to integrate high-performance AlGaN/GaN-based optoelectronic and microwave devices on a single chip.

• 出版日期2011-5