Fabrication And Properties Of UV Detector And Acetone Gas Sensor Based On Sb Doped ?-Ga₂O₃ Thin Films/p-Si Heterojunction

As a wide-bandgap semiconductor,?-Ga₂O₃has good characteristics of 4.9e V direct bandgap,large breakdown field,stable chemical and physical properties and easy to preparation.These characteristics make?-Ga₂O₃has a wide application prospect in optoelectronic devices,power devices,gas sensors and transparent conductive layers and other fields.In this paper,different antimony contents?-Ga₂O₃thin films were deposited by chemical vapor deposition on p-type Si substrates and self-powered solar-blind ultraviolet photodetectors and acetone gas sensor were fabricated based on Sb doped?-Ga₂O₃thin films/Si heterojunction,and the detection performance of photodetectors and gas sensor is studied.The main achievements are as follows:(1)Sb doped?-Ga₂O₃thin films with different contents were grown on p-type Si substrates by chemical vapor deposition.The self-powered solar-blind ultraviolet photodetectors of Sb:?-Ga₂O₃thin films/Si heterojunction which can work under zero bias voltage has been prepared.The results indicate that the surface morphology and crystal quality of Sb doped?-Ga₂O₃thin films are improved with the increase of Sb doping amount,which is mainly caused by the fact that amount of Sb can act as surface activator.The responsivity at 254nm reached up to 29m A/W without a power supply.Moreover our device also has a high I_photo/I_darkratio over 1.28×10⁵and the response time and recovery time of 0.1s without bias,and the device has good stability and repeatability.(2)We have investigated of annealed Sb doped?-Ga₂O₃thin films in O₂and in N₂.Research show that recrystallization occurs in N₂annealed and O₂annealed thin films,and the grain size significantly increased on annealing.This indicates an improvement in crystal quality after annealing.We also studied the UVdetection characteristics based on annealed?-Ga₂O₃thin films/Si heterojunction.The research show that not only the properties of the annealed devices are obviously enhanced,but also O₂annealed devices has the most obvious performance improvement.The I_photo/I_darkratio at 254nm reached up to 5.4×10⁵without a power supply.(3)Sb doped?-Ga₂O₃thin films were deposited by chemical vapor deposition on p-type Si substrates and acetone gas sensor were fabricated based on Sb doped?-Ga₂O₃thin films/Si heterojunction.Research show that the maximum sensor response of sensors were found upon exposure toward acetone vapor at 200ppm concentration and room temperature with the value of 30.7.The fast response time and recovery time of sensors were found upon exposure toward acetone vapor at 10ppm concentration and room temperature with the value of 14s and13s,respectively.In addition,we found that the sensor can detect acetone gas with concentration of 10-200ppm,and has good stability and repeatability.