New Field-Effect Resistive Pd/Oxide/AlGaAs Hydrogen Sensor Based on Pseudomorphic High Electron Mobility Transistor

Abstract

A new and interesting field-effect resistive hydrogen sensor that is based on a Pd/oxide/AlGaAs pseudomorphic high electron mobility transistor (PHEMT) structure, is fabricated and studied. A simple model is proposed to elucidate the hydrogen adsorption and sensing mechanisms. The reaction of the device studied with hydrogen gas results in a considerable decrease in channel resistance. The resistance curves of the hydrogen response demonstrate that this device shows good reversible, repeatable, and concentration-dependent properties. In comparison with other resistor-type hydrogen sensors, the device studied presents the significant advantages of high detection sensitivity (24.7% in 9970 ppm H2/air gas) and low detection limit (< 4.3 ppm H2/air) at room temperature. Furthermore, the device studied exhibits small resistance (30 Ω) and small operating voltage (< 0.3 V), which are superior to those of other resistive sensors with typically larger resistances ranging from kΩ to MΩ and voltages greater than 1 V.