Optical Properties Of Doped GaSb Films And GaSb Heterojunction

GaSb has many excellent properties and wide application prospects.However,for intrinsic GaSb,usually P type conductive and the acceptors defects limit its application in many areas.In addition,GaSb easily oxidizes under atmospheric conditions forming an oxide layer,this always leads to the high surface recombination velocity and large leakage currents that hinder the enhancement of devices' performance.Improving the optical properties of GaSb material is the research object,through the GaSb material doped with N type and P type dopant atoms and MgO dry passivation treatment,regulating luminescence properties of GaSb films,which laid the foundation for the application of GaSb material in devices.The research content of this paper mainly includes the following two parts:Molecular beam epitaxy was used to prepare the high-quality doped GaSb epilayers on semi-insulating GaAs substrate,we choose the group-VI elements Te as the n-type dopant and group-II elements Be as the p-type dopant;The crystal structures of the samples were analyzed by X-ray diffraction,the epitaxial layers of both p-type and n-type Ga Sb films show great quality;Detailed analyses of the changes of native lattice defect after GaSb doped with Te and Be according to PL spectra.The PL of Te doped GaSb introduce Te related donor-acceptor transition,located in 0.729 eV at 10 K.Be will reduce the concentration of acceptor defects,so only the exciton peak was observed in PL spectrum.The different MgO films were grown on GaSb by atomic-layer-deposition system;X-ray photoelectron spectroscopy was used to measure the valence-band offset(?EV)of MgO/GaSb heterostructure,a type-I band alignment of MgO/InP heterostructure was obtained,it is shown that after deposition of MgO,electrons and holes are localized in the GaSb layer,which leads to increase the recombination rate of electrons and holes and the luminescence efficiency of GaSb materials;The PL emission arises from band-to-band recombination well away from the sample surface,the spectral shape and characteristics of the PL emission in all samples did not change with passivation treatment,the luminous intensity of MgO/GaSb was improved to 1.5 times compared with undoped GaSb at room tempreture,it is shown that deposited MgO film on GaSb have enhanced the luminescence intensity.Compared with the undoped GaSb,luminescence quality of grown MgO film on GaSb was improved,and the half width of each peak became narrower,forming separate peaks in PL spectra at low temperatures.