Photoelectric Properties And Related Devices Of Pulsed Laser Deposited Gallium Oxide Thin Films

Gallium oxide has a wide band gap and a relatively stable structure.It was a transparent oxide semiconductor material with excellent optoelectronic properties.It was widely used in solar blind detectors,power rectifiers,field effect transistors,gas sensors,light-emitting diodes and solar cells.At present,the third-generation semiconductor materials are dominated by gallium nitride and silicon carbide,but their breakdown voltage is relatively low,which that limits their application in high-power devices.In recent years,gallium oxide has been widely used in the fields of power electronics and ultraviolet optoelectronics as a high-performance,economically feasible ultra-wide band gap semiconductor.Its critical field strength is relatively large(theoretical value is as high as 8 MV/cm).Due to optical anisotropy,its band gap range4.5-5.3 e V,which can be used in high-power electronic devices.In future,it is expected to become the main material of the third generation semiconductor semiconductors.In this study,pulsed laser deposition(Pulsed Laser Deposition,PLD)technology is used to deposited gallium oxide films(Ga₂O₃)on c-plane sapphire(Al₂O₃)substrates at different temperatures(room temperature-800?),and the amorphous gallium oxide films are processed.An annealing study was conducted to explore the effects of different annealing temperatures(400-1000?)and atmospheres(oxygen,nitrogen and hydrogen mixed gas)on amorphous gallium oxide films.X-ray diffractometer(XRD)was used to characterize the film crystal structure;atomic force microscope(AFM)?scanning electron microscope(SEM)to analyze the surface morphology of the film;ellipsometer(SE)and ultraviolet-visible spectrometer(UV-Vis)analyze the optical properties of the film,and study the effects of different growth temperatures,different annealing temperatures and atmospheres on the crystal structure,surface morphology and optical properties of the film.Simulate and analyze the gallium oxide MSM structure detector.This article can be divided into the following parts:(1)To study the mechanism of pulsed laser deposition of gallium oxide thin films,a pulsed laser deposition technique was used to prepare gallium oxide thin films at room temperature-800?.As the growth temperature increases,the deposition rate decreases.The deposition rate decreases smoothly within 400?,and the deposition rate decreases rapidly above 450?,and shows a linear decrease trend.(2)To study the effect of annealing temperature on the gallium oxide film,the uncrystallized sample in(1)was thermally annealed.Single crystal?-Ga₂O₃ can be obtained through thermal annealing at different temperature(400-1000?)and atmosphere(oxygen,nitrogen and hydrogen mixture).The results showed that the quality of the film grown at room temperature is poor,even if the annealing temperature at1000?,the film crystallinity is still poor;the film was grown at 400?is annealed in an oxygen atmosphere,and the temperature is 700?to obtain with better crystallinity?-Ga₂O₃ thin film;in a nitrogen-hydrogen mixture atmosphere,a film grown at 400?can be annealed at 500?to obtain high-quality single-crystal?-Ga₂O₃.Annealing temperature above 900?found the presence of Al element;at the same time,it was found that annealing with nitrogen and hydrogen gas mixture would inhibit the crystallization of gallium oxide film at a temperature above 800?.(3)Based on the above experimental results,the gallium oxide MSM structure(metal-semiconductor-metal)detector is simulated based on Silvaco TCAD.By changing the optical band gap(4.8-5.4 e V)to study the performance of the device,it is found that with the increase of the optical band gap,the maximum photocurrent of the detector decreases with the increase of the optical band gap.The ratio is as high as 10⁷times.The Silvaco TCAD simulation conclusion proves that the MSM structure detector made of gallium oxide material has good performance,which brings important reference value to practical application and research,and brings a theoretical basis for the preparation of gallium oxide MSM detector.