Highly Sensitive Hydrogen Detection Using a Pt-Catalyzed InN Epilayer

Abstract

The current response to hydrogen for a biased ultrathin (∼10 nm) In-polar indium nitride (InN) epilayer with a catalytic Pt film on top has been investigated. The Pt–InN sensor shows a high current variation ratio of ∼400% with response/recovery times of less than 1 min while exposed to 2000 ppm H2/air at 150 °C. Even at room temperature, a current variation ratio of 81% was observed under the same gas environment. At 125 °C, the detection limit was experimentally found to be less than 5 ppm. In comparison with a bare InN sensor, the Pt catalyst enhances the current variation by 375 times at 2000 ppm H2/air.