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.