Ammonia sensing properties of a Pt/AlGaN/GaN schottky diode

Tai You Chen, Huey Ing Chen, Yi Jung Liu, Chien Chang Huang, Chi Shiang Hsu, Chung Fu Chang, Wen Chau Liu

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)


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 °C, significant ammonia detection is observed under a low ammonia concentration of 35-ppm NH3/air. Moreover, a high ammonia sensing response of 18300% and the large Schottky barrier variation ratio Δbb/air of 13.8% are observed upon exposure to a 1% NH3/air gas at 150 °C. The presence of dipoles at the metalsemiconductor 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.

Original languageEnglish
Article number5746515
Pages (from-to)1541-1547
Number of pages7
JournalIEEE Transactions on Electron Devices
Issue number5
Publication statusPublished - 2011 May

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering


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