Infrared Modulation Photoluminescence Spectroscopy Of Area Array Materials InAs/GaSb Superlattice And InAsSb

The step-scan Fourier transform infrared(FTIR)modulation photoluminescence(PL)spectrum can effectively eliminate the interference of environmental background thermal radiation,and significantly improve the spectral signal-to-noise ratio and the detection ability of weak signals.Therefore,it is considered to be a non-contact and fast response experimental characterization method and is widely used in the research and analysis of the electronic band structure,defects/impurities,band tail states and other properties of narrow band gap semiconductor materials.In As/Ga Sb superlattices infrared focal plane array(FPA)photodetectors have important military application value.As an absorption layer,In As/Ga Sb superlattices have the advantages of continuously tunable band gap,reduced Auger recombination efficiency and large effective electron mass.The In As Sb thin film transport layer in the complementary barrier structure has the lattice constant that matches that of In As and Ga Sb,and has good carrier transport performance.However,both In As/Ga Sb superlattices and In As Sb thin films have in-plane spatial fluctuations of photoelectric characteristics caused by dislocations and defects.This results in limited pixel response uniformity and imaging performance of infrared FPA.Therefore,how to understand and clarify the influence of superlattice absorption layer and In As Sb transport layer on infrared FPA pixel response nonuniformity from mechanism has become an important basic scientific problem to improve infrared FPA imaging performance.Based on this,in this paper,the characteristic methods of single-piexl and spatially resolved and two-dimensional mapping modulated infrared PL are used to investigate the photoelectron transition characteristics and in-plane distribution uniformity of In As/Ga Sb superlattice absorber layer and In As Sb transport layer.The main work and research progress include:(i)The transition characteristics of 1e-1hh in In As/Ga Sb superlattices and the defect/impurity and interband transition mechanisms of In As Sb are determined.By analyzing the regulating effects of In As/Ga Sb superlattice interface on temperature sensitivity and phonon scattering,a reference theoretical model for interface optimization is proposed.(ii)The nonuniformity contribution of In As/Ga Sb superlattice and In As Sb layers to the device is studied,and the nonuniformity contribution of In As/Ga Sb superlattice surface and interface is analyzed emphatically.The results show that the contribution of In As/Ga Sb superlattice nonuniformity is 2-3 times that of In As Sb.The surface damage results in a 5-fold increase in peak position energy nonuniformity,a 7-fold increase in linewidth nonuniformity,and a 4-fold increase in integrated intensity nonuniformity of In As/Ga Sb superlattice.On the one hand,this work demonstrates and verifies the effectiveness of modulated infrared and mapping PL methods in analyzing the uniformity of materials,on the other hand,it clarified the influence of in-plane uniformity of infrared photoelectronic characteristics of In As/Ga Sb superlattice absorption layer and In As Sb transport layer on FPA imaging quality.This result is expected to provide a model scheme reference for infrared FPA imaging quality optimization project.