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 H 2 /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 H 2 /air. © 2010 The Japan Society of Applied Physics.