Methane detection using Pt-gated AlGaN/GaN high electron mobility transistor based Schottky diodes

Pt-gated AlGaN/GaN high electron mobility transistor based Schottky diodes were employed to detect methane. A detection sensitivity >100 was obtained for the diodes under reverse bias, and this was one order of magnitude higher than the sensitivity of the diodes operated under forward bias. A new method to extract the response time was demonstrated by taking the derivative of diode current, allowing a reduction in the sensor response time by 80%. Methane sensing experiments were conducted at different temperatures, and an Arrhenius plot of the data determined an activation energy of 57 kJ/mol for the sensing process. (C) 2013 American Vacuum Society.