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Study On Optical And Structural Properties Of Containing In Photoelectric Semiconductor Materials

Posted on:2019-07-04Degree:MasterType:Thesis
Country:ChinaCandidate:Y L LiangFull Text:PDF
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Indium Antimonide(InSb)based compound semiconductor materials have the highest carrier mobility and minimum bandgap at room temperature among the ?-? semiconductor materials,and excellent electron transport performance under the action of an electric field.Therefore,it is an important material for making infrared detectors and imaging systems with wavelength of 3-5 ?m.InAlN has a tunable direct bandgap,changing from 0.7 eV(InN)to 6.2 eV(AlN),which covers a wide spectral range from infrared(IR)to ultraviolet(UV).These meet the needs for the full spectrum of optoelectronic device production.In recent years,the investigation and application development of InAlN/GaN-based mobility transistors has attracted people's widespread attention.The InSb/GaAs and InAlN/GaN heterostructures discussed in this paper have very important research value for the design and fabrication of optoelectronics,microelectronic structures,high temperature and high power semiconductor devices in the future.In order to further improve the crystal quality of InSb and InAIN thin films and promote the industrial production of semiconductor materials,we need to understand the temperature-dependent optical properties,the internal information of the crystal structure,the stress distribution,and the like of such materials.Based on these factors,multi-spectral technology characterization and analysis of InSb/GaAs materials were performed,and temperature-dependent spectroscopic ellipsometry analysis was performed on InAlN/GaN materials in this paper.This paper first introduces and elaborates the basic properties of InSb and InAIN materials and their current research status and existing problems.Then introduce the basic principles and data analysis of the non-destructive characterization techniques-spectroscopic ellipsometry,X-ray absorption fine structure spectroscopy and Raman scattering spectroscopy.On this basis,the experimental results were obtained and analyzed by characterizing the semiconductor material through a variety of characterization techniques to obtain the optical properties and microstructure information of the material.The main research contents are as follows:(1)InSb thin films grown on GaAs substrates with different ?/?ratios by metalorganic chemical vapor deposition(MOCVD),were performed by spectroscopic ellipsometry under the condition at a spectral range of 200 to 1680 nm(0.74 to 6.2 eV)and a temperature range of 25 to 300?.The processing and analysis of experimental data by using the Tauc-Lorentz oscillator model,which can obtain the optical constants and film thickness of the InSb film at these spectral and temperature range.The second derivative of the dielectric function of the InSb thin film give a more accurate temperature characteristic of the absorption peak position.The research results shown that the InSb absorption peaks shift toward longer wavelength with increasing temperature(25-300?).The spectral of InSb thin film obviously changes when temperature higher than 250?,which may be caused by irreversible oxidation under high temperature conditions.This explains that the InSb/GaAs materials have a certain high temperature limitation,which provided a reference value for studying the energy band structure of materials.(2)The X-ray absorption fine structure spectra of the In K-edge of InSb thin films were investigated by the synchrotron radiation experiment.The spectra were processed and analyzed by the Ifeffit software.The coordination number and bond length of In-Sb are obtained from fitting the EXAFS in R-space.The research results shown that different I ratios have little effect on the In-Sb bond length.The best ?/? ratio was found to be 4.78 by comparing the results of fitting with a theoretical model.(3)Raman scattering spectra with an excitation wavelength of 514 nm was used to investigate the effect of ?/? ratios on the crystal quality of InSb thin films.The phonon frequency,the full width at half maximum,and the peak area ratio of TO and LO mode were obtained by Lorentz fitting of the TO-LO spectral region.XRD spectra of angles(2?)ranging from 55° to 69°were scanned on the InSb thin film,and Lorentz fitting of the InSb(400)peak was performed to obtain FWHM.Comprehensive Raman and XRD results show that ?/?= 4.78 is the growth parameter of a good quality InSb thin film sample.These results can provide a reference for the growth of samples,but also provide useful information for the design of high-performance InSb infrared optical thin-film devices.(4)In order to investigate the optical properties of InAIN with various temperature,InAIN alloy was characterized by temperature-dependent(25-600?)spectroscopic ellipsometry in the spectral range of 193-1650 nm.The optical constants(n,k and a)of InAIN thin film were fitted by temperature-dependent ellipsometry using the Tauc-Lorentz oscillator model.At the temperatures of 50-600?,it was seen that the optical bandgap decreases from 4.56 to 4.35 eV and the energy corresponding to the peak of refractive index decreases from 4.61 to 4.37 eV between.Both of them decrease with the increase of temperature,which accords with the law of Varshni equation.In addition,there have no significant change in measured spectra and optical parameters within the setted test temperature,which indicates that the InAIN alloy has a higher thermal stability and has no effect on the crystal structure of the material's optical properties.
Keywords/Search Tags:InSb, InAIN, ellipsometric spectroscopy spectra, X-ray absorption fine structure spectroscopy spectra, Raman scattering spectra
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