Effect Of Irradiation On The Structure And Optical Properties Of GaSb Materials

As a typical III-V semiconductor material,GaSb,with a narrow band gap,a high electron mobility and a high saturation speed,is a potential material for the preparation of mid-infrared semiconductor devices.GaSb-based devices have been used in space solar cells and space exploration in recent years.The radiation damage of semiconductor devices in the space environment has attracted extensive attentions,and many efforts have been made to study the damage of III-V semiconductor devices.However,the radiation damage associated with GaSb materials and GaSb-based devices is still in primary stage.In this paper,the structure and optical properties of Te-doped GaSb,homo-epitaxial GaSb thin films and hetero-epitaxial GaSb thin films have been investigated by XRD and PL before and after irradiation,the process and mechanism of high energy electron irradiate GaSb material have been obtained.The effects of electron irradiation on the structure and optical properties of Te-doped GaSb materials are studied.The results show that the concentration of defects in Te-doped GaSb increases,the blue shift of XRD,the increase of FWHM,the blue shift of PL peak and the increase of peak intensity are observed.This is due to the presence of V_Gaa Ga_SbTe_Sbb composite defects in Te-doped GaSb.Due to the low binding energy of V_Gaa Ga _SbTe_Sb,high electron energy can cause V_GaGa_Sbb Te_Sb defects to be decomposed into V_GaGa_Sb and Te_Sbb during irradiation,which increases the defect concentration in the material and decreases the material quality.The effects of electron irradiation on the structure and optical properties of homo-epitaxial GaSb thin film materials and hetero-epitaxial GaSb thin film materials which growth by MBE are also studied.It is found that the peak position of the XRD diffraction peaks and the FWHM of the homo-epitaxial GaSb thin film materials do not change after irradiation.The PL peak has a weak blue shift,and the peak intensity is weakly enhanced.The anti-irradiation capability of the film is significantly better than that of Te-doped GaSb material.This is because there is no V_GaGa_Sbb Te_Sb defect which has low binding energy in the un-doped homo-epitaxial GaSb films,which can be ingnored,so the anti-irradiation performance is better.For hetero-epitaxial GaSb thin film materials,the XRD diffraction peak position of the GaAs substrate does not change,and the FWHM broadens,which means that the crystal quality in the substrate decrease.For GaSb thin film,both the XRD diffraction peak position and FWHM retain constant.On the other hand,the peak of PL after irradiation is almost unchanged,and the peak intensity is greatly changed.The peak intensity from GaSb is increased.This is due to the fact that there is a large stress at the interface between GaAs and GaSb during hetero-epitaxy growth.Under the irradiation of high electron energy,the concentration of defects in GaSb thin film which caused by the stress are changed.