| With the rapid development of electronic technology and related industries,the first-generation semiconductor materials represented by elemental semiconductor Si and the second generation semiconductor materials represented by compound semiconductors such as GaAs,GaP and InP can no longer meet the development requirements of modern electronic industry.Therefore,the third-generation compound semiconductor materials,such as ?-? nitride semiconductors,gallium oxide,zinc oxide and silicon carbide,have developed rapidly.AIN,Ga203 and their related compounds have many excellent physical properties,so they are widely used in many fields of optoelectronic devices.In order to increase the efficiency of radiation recombination and reduce the adverse effects of polarization field on devices,the preparation and research of semi-polar and non-polar nitride semiconductors have attracted wide attention.In addition,in order to realize the application of Ga203 in P-type conductivity,the study of introducing Zn to form ZnGa204 compounds in the preparation of materials has attracted wide attention,but the related research is still relatively deficient.In order to further improve the preparation quality of AIN semiconductor materials and Ga203 and related materials,and to further understand the physical properties of AIN and Ga203 materials,it is particularly important to study the effects of different growth conditions on the optical,surface and microstructures of materials by means of various characterization methodsThe main contents of this paper include the following aspects(1)A series of AIN films with the same growth conditions were grown on different surfaces(A-,C-,M-and R-surfaces)of sapphire substrates by MOCVD,and various technical tests were carried out.Firstly,the crystal orientation of AIN thin films was analyzed by X-ray diffraction.The effect of substrate nitriding pretreatment on the crystal orientation of AIN thin films was also studied.The grain size,dislocation density and micro-strain of the samples were obtained byusing the relevant calculation equations(2)The surface properties of AIN thin films were measured by X-ray photoelectron spectroscopy(XPS)and scanning electron microscopy(SEM).The surface morphology,chemical species and oxide film thickness,energy band offset and energy band arrangement were obtained(3)For AIN films grown on A-plane,M-plane and R-plane Sapphire respectively,a clear E2(high)phonon mode was observed by Raman scattering spectroscopy.The half-width of Raman peak is simulated by using spatial correlation model(4)Four samples of ZnGa204 in sapphire were studied.The ellipsometric parameters of the samples were obtained by fitting the ellipsometric lines.The optical constants n and K of the samples and the thickness and surface roughness of the films were also obtained by fitting.XRD measurements show that the sample is ZnGa2O4,and the position of the diffraction peak shifts with the flow rate of Zn(5)Temperature-dependent elliptical polarization spectroscopy was used to measure the band gap at different temperatures.Then the band gap of samples at room temperature was measured by optical transmission spectroscopy at room temperature(6)XPS full scan spectrum,element ratio,band arrangement and band offset of ZnGa2O4 were obtained by XPS. |
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