Research On Growth And Performance Of Largely Mismatched InGaAs/InP Detector Materials With Low Background Concentration

Largely lattice-mismatched InGaAs/InP detector materials have many important applications in aerospace remote sensing and other fields.Different carrier concentration and lattice mismatch have significant effects on material properties.Low background carrier concentration materials are the basis of high quality and large mismatched InGaAs/InP materials.In this paper,largely mismatched InGaAs/InP detector materials with wavelength extended from 1.9μm to 2.5μm were grown by molecular beam epitaxy.The effects of growth process parameters and carrier concentration on the properties of largely mismatched InGaAs/InP materials were studied,and the effects of different lattice mismatch on the properties of InGaAs/InP detector materials were analyzed.The main contents and conclusions of this thesis are as follows:1.The effects of molecular beam epitaxy growth conditions on the properties of largely lattice mismatched InGaAs materials were studied.The effects of growth temperature,Ⅴ/Ⅲ ratio and As molecules on photoluminescence and X-ray diffraction peak intensity of In_0.75Ga_0.25As materials were analyzed,and the background carrier concentration and mobility were optimized.Results show that moderate growth temperature and Ⅴ/Ⅲ ratio can improve the lattice quality,reduce the non-radiative recombination and reduce the background carrier concentration.2.Focusing on the key material properties of carrier concentration,the effects of different carrier concentration on the surface morphology,optical and electrical properties of In_0.75Ga_0.25As extended wavelength material with absorption wavelength of 2.2μm were studied.The materials were characterized by microwave photoconductive decay carrier lifetime measurement,high resolution X-ray diffraction,temperature-dependent photoluminescence and Hall measurements.As the carrier concentration increases,the minority carrier lifetime decreases,the photoluminescence intensity and X-ray diffraction intensity decrease.3.In order to solve the problem of different lattice mismatch of InGaAs detector materials caused by different indium composition,the surface,structure and optoelectronic properties of InGaAs detector materials with different lattice mismatch were studied,and the effect of lattice mismatch on the material properties was analyzed.There is little difference in surface,optical and electrical properties of high In component InGaAs detector materials with lattice mismatch.The distance between InGaAs epitaxial peak and InP peak of X-ray diffraction increases with the increase of In composition,and the overall upper half peak width increases with the increase of lattice mismatch.The flatness of lattice mismatch materials decreases with the increase of lattice mismatch.