Pt/GaN Schottky Diodes for Highly Sensitive Hydrogen Sulfide Detection

Pt/GaN Schottky diodes were fabricated for detecting hydrogen sulfide at 200 degrees C. Ga-face GaN was grown on c-plane sapphire substrate by a metal-organic chemical vapor deposition (MOCVD) system. Hydrogen sulfide was mixed with nitrogen and detected from 0.1 similar to 10 ppm with the Pt/GaN Schottky diodes. Hydrogen sulfide caused the current increase in both forward and reversed bias of the Schottky diode. Real-time detection of the hydrogen sulfide was conducted at a forward bias 1.18 V in nitrogen ambient. The sensors show good linear dependence of the current change at forward bias versus the H2S gas concentration. The sensitivity in the two ranges from 0.1 similar to 1 ppm and 1 similar to 10 ppm of hydrogen sulfide, are 14.62 and 5.844 mu A/ppm, respectively. The detection limit of the sensor is around 0.2 ppm of hydrogen sulfide at the forward bias at 200 degrees C. The results show that the Pt/GaN Schottky diodes are promising for low cost and high sensitivity hydrogen sulfide detection. (C) The Author(s) 2016. Published by ECS. All rights reserved.