Electrospinning Preparation And Properties Of Ga₂O₃/In₂O₃ And GaN/InN

Novel semiconductor materials have been well developed in recent years. Among which, Ga2O3/In2O3 and GaN/InN materials, with quantum size effects, dielectric confinement effects and the unique nano-diameter structure, have attracted great interest owing to their excellent optical, electrical, gas sensing and photocatalysis properties. All these special properties make them widely applied on novel device and technology with broad prospect. One dimensional oxide semiconductor nano-material is an important functional material that has important significance in practical applications. Electrostatic spinning technology has the advantage of good controllability, simple process and low cost. The production has high specific surface area, high ratio of length to diameter and the unique mesh structure. In this thesis, In2O3, Ga2O3, GaN, InN and In2O3/Ga2O3 composite nanofibers have been prepared by electrostatic spinning technology.In2O3 and Ga2O3 nanofibers were prepared by electrospinning using PVP and Ga(NO3)3/In(NO3)3 as precursor. The electrospun nanofibers were then heat treated in air. The nanofibers have been characterized systemically by XRD, FT-IR, Raman, SEM and TG. UV-vis, PL spectra and the gas sensitive were further investigated. The results indicated that In2O3 and Ga2O3 nanofibers with uniform morphology are monoclinic and body-centered cubic structure, respectively. Their diameter ranges from 100～300 nm and 200～400 nm, respectively. The best heat treatment temperature for fiber is 900℃. FT-IR and UV-Vis spectra show a blue shift, Raman peak shows a red shift. Ga2O3 nanofibers obtained broad 452 nm and 526 nm blue and green light emission and In2O3 nanofibers obtained broad 612 nm orange light emission. In2O3 nanofibers gas sensor show stability for the ammonia, methanal and alcohol solution and exhibit well performance of selectivity to ammonia and methanal at 1000 ppm ammonia concentration and 5 V working voltage. Based on electrospinning of In2O3 and Ga2O3 nanofibers, the GaN and InN nanofibers were prepared by further nitrogen treatment. The nanofibers have been characterized systemically by XRD, Raman, SEM, TEM, TG. The UV-vis spectra, PL spectra of GaN nanofibers and photocatalysis of rhodamine 6G were investigated. The results indicated that nanofibers with uniform morphology have the hexagonal wurtzite structure. The diameter of GaN and InN was 100～200 nm and 200～400 nm, respectively. The best heat treatment temperature for GaN and InN nanofibers were 850 and 600℃, and corresponding heating preservation time were 2 h and 8 h, respectively. GaN nanofibers has better stability than InN nanofibers under both nitrogen and air atmosphere. UV-Vis spectra shift blue and Raman shift red. GaN nanofibers obtained broad 612 nm red light emission. GaN nanofiber shows excellent photocatalysis properties to rhodamine 6G. It took 2 h to degrade rhodamine 6G solution with the concentration of 10-5 mol/L.composite nanofibers have been successfully prepared through simply improved equipment. XRD, SEM and EDS have been applied to characterize the In2O3/Ga2O3 composite nanofibers. The results indicated that composite nanofibers with uniform morphology has the diameter range from 100～400 nm. The best heat treatment temperature is 900℃.