Effect of CO on Characteristics of AlGaN/GaN Schottky Diode

Pt Schottky diode gas sensors for CO are fabricated using AlGaN/GaN high electron mobility transistor (HEMTs) structure. The diodes show a remarkable sensor signal (3mA, in N2; 2mA in air ambient) biased 2V after 1% CO is introduced at 50°C. The Schottky barrier heights decrease for 36meV and 27meV in the two cases respectively. The devices exhibit a slow recovery characteristic in air ambient but almost none in the background of pure N2, which reveals that oxygen molecules could accelerate the desorption of CO and offer restrictions to CO detection.