The Heteroepitaxial And Characteristics Of GaSb Based Materials

Near infrared semiconductor lasers have substantial prospects in military and civil applications.As the representation of GaSb based semiconductor materials,GaAsSb ternary has become an important candidate material for the active region in near infrared strained quantum well lasers due to its adjustable of bandgap in a wide range.The active region is the core of the semiconductor laser device.Consider to the insufficient of research on GaAsSb alloy and GaAsSb/AlGaAs strained quantum well material,we plan to grow high quality GaAsSb/AlGaAs strained quantum well for prepare GaAsSb/AlGaAs strained quantum well laser device.In order to attain this goal,we optimize the epitaxy growth condition and analysis the material properties of GaSb,GaAsSb and GaAsSb/AlGaAs strained quantum well,respectively.The main research works are carried out as follows:1.The GaSb epitaxial layer was growth by molecular beam epitaxy(MBE)technique,and the epitaxial growth conditions was optimized to obtain the high quality GaSb materials.The influence of defects on the optical properties was confirmed by further photoluminescence spectra analysis in the hetero-epitaxial GaSb films.In order to improve the optical properties of hetero-epitaxial GaSb,MgO passivation method was used,and the optical intensity was enhanced after passivation.This part is the basic research for further analysis on epitaxial growth and optical properties of GaAsSb alloy.2.The hetero-epitaxy GaAsSb alloy was prepared by using MBE technique,and the alloy component was controlled by manipulating the As/Sb beam ratio.The optical properties of the alloy were analyzed by PL spectra.The emission evolution behavior of localized states variation with the Sb component was obtained.It is proved that the transitions of localized carriers are important carrier recombination mechanism in GaAsSb.In order to understand the nature of localized state,the GaAsSb alloy was treated by the rapid thermal annealing(RTA)technique.The modulation effect of annealing temperature on the localized states was investigated,and the regularities of the localized state properties with the annealing temperature were obtained.This part provides the basic research for the epitaxial growth condition,optical properties analysis and improvement of the GaAsSb/AlGaAs strained quantum well.3.According to the theory of strained quantum well,the variation rule of the light and heavy holes band with the component was obtained in the GaAsSb/AlGaAs strained quantum well.The GaAs0.92Sb0.08/Al0.3Ga0.7As multiple strained quantum wells with wavelength of 935 nm was designed and fabricated.The optical properties of GaAs0.92Sb0.08/Al0.3Ga0.7As multiple strained quantum wells were investigated experimentally.According to the analysis of XRD pattern and PL spectra,we confirmed that the strained quantum well was consistent with the design,and observed the phenomena of heavy hole exciton and light hole exciton coexist in room temperature.In order to study the optical properties of the strained quantum well,the sample was treated by RTA technique.The manipulate effect of annealing temperature on strained quantum well sample was investigated.The results show that the annealing temperatures have great influence on optical properties of the strained quantum well samples.It was confirmed that the important factors were localized states,strain and the interfacial mixing effect in strained quantum well.In this part,the high quality GaAs0.92Sb0.08/Al0.3Ga0.7As strained quantum well material was fabricated successfully and the adjustment of strained MQWs emission intensity and wavelength was realized by using rapid thermal annealing method.In this thesis,the investigation on the GaAsSb alloy and GaAsSb/AlGaAs strained quantum well provides the basic investigation for preparation and performance adjustment of the strained quantum well lasers.