Studies On Fabrication,Microstructure And Optoelectronic Properties Of Indium Nitride Thin Films

The research of the new semiconductor thin film material has been studied for many years, it is one of the hot topics in the research field of new functional materials. In ?-? compound semiconductors, Indium nitride?InN? is a new type of semiconductor material with excellent performance, which has attracted much attention of researchers at home and abroad, due to its special physical properties and potential application value. Theoretical studies show that the InN material has the highest mobility, peak rate,electron drift rate, peak rate and the minimum effective electron mass in the group ? nitride semiconductor materials, these characteristics make it has a unique advantage in the application of high frequency and high speed transistors. With the appearance of high quality InN thin films with 0.7 eV band gap prepared by molecular beam epitaxy, InN materials have received more and more attention. At present, domestic and foreign researchers have studied the lattice vibration, electrical transport, nonlinear optics,photoluminescence and other characteristics of InN materials. The research indicates that InN is expected to be the best material for the realization of high frequency and high speed transistors, heterojunction field effect transistors, ultra fast optical switching devices, optical limiting devices and high performance solar cells. This paper starts with the preparation, microstructure and photoelectric properties of InN films, and a series of studies have been carried out on the growth conditions, characterization and optical properties of InN thin films.In this paper, we calculated the electronic structure and transport properties of InN materials, and prepared the InN thin films and InN heterojunction devices. The thin films and devices were systematically analyzed by XRD, AFM, SEM, EDS, spectrophotometer and Keithley 2400, respectively. The effects of growth parameters on the morphology and properties of InN thin films and the preparation and properties of InN heterojunction devices were studied. The specific research contents are as follows:1. The structural parameters, elastic constants, thermal transport properties, band structure, density of states, electron localization function and electronic transport properties of wurtzite InN have been investigated by first-principles calculations and semiclassical Boltzmann theory using VASP and WIEN2 k.The thermoelectric properties of InN materials were studied to explore its application in thermoelectricfield.2. InN thin films were grown on Si?111? and quartz substrates by RF reactive sputtering at different N2/Ar ratios. The composition, crystalline state, morphology and optical properties of the films were characterized. The effects of different N2/Ar ratio on the morphology and properties of InN thin films were studied.3. InN thin films were grown on Si?111? and quartz substrates at different substrate temperatures by RF reactive sputtering. The crystalline state, morphology and optical properties of the films were characterized. The effects of different substrate temperature on the morphology and properties of InN thin films were studied.4. The Au/n-InN/p-GaN/Au heterojunction devices were prepared by the optimized growth parameters of InN thin films. The characteristics of InN thin films on GaN substrates were characterized, and the ?-? characteristics of Au/n-InN/p-GaN/Au heterojunction devices were also studied.5. The Au/InN/Nb:SrTiO₃/In heterojunction devices were prepared by the optimized growth parameters of InN thin films. The characteristics of InN thin films on Nb:SrTiO₃ substrates were characterized, and the ?-? characteristics of Au/InN/Nb:SrTiO₃/In heterojunction devices were also studied preliminary.