High temperature sensing characteristics of a high performance Pd/AlGaN/GaN Schottky diode hydrogen sensor obtained by oxygen gettering

摘要

High temperature sensing characteristics of a Pd/AlGaN/GaN Schottky diode hydrogen sensor were investigated By applying an oxygen gettering process, the diode showed very small leakage currents even at elevated temperatures. On exposure to 10 Torr hydrogen in an air ambient (200 Torr), the diode showed a large current change of four orders of magnitude. The observed sensing behaviour could be fitted to a theoryrnbased on the sensing mechanism involving Schottky banter height reduction due to interface dipole formation by atomic hydrogen. The diode showed much improved characteristics at 110 ℃ than at room temperature. This surprising result is explained in terms of the current transport mechanism; The diode showed much better sensing characteristics than those of GaAs and InP.