Research on hydrogen gas sensors based on Pd/Ga2O3/AlGaN/GaN HEMT
Since H2 gas is easy to fire and explore,large amounts of H2 sensors with fast response are required for the monitoring of early warning and forecasting in all processes of H2 energy,including the H2 refueling station,the transportation vehicle,and the H2 vehicles.Herein,based on precious metal Pd as a gate Pd/Ga2O3/AlGaN/GaN high electro mobility transistor(HEMT)type sensors are investigated.Ti/Al/Ti/Au are used as the source/drain electrodes and the Pd gate is used as sensitive electrode.Results show that on/off ratio of transistor is 3.58×107.With the influence law of various thicknesses of Ga2O3 insertion layer on H2 response characteristics are experimentally investigated.With the thickness increase of the Ga2O3 of insertion layers,the saturation volume significantly inceases from 1×10-3 to 7×10-3.For the device with 10 nm thick of Ga2O3 layer,it has the best overall performances.This sensor has satuation fraction of 5×10-3 and high response value of 4300% at 1×10-3.In particular,its response speed is ultrafast in H2 gas detection and the fastest speed is 2 s.