Growth And Detector Of Sb Superlattice Long Wavelength Infrared Materials

The long wavelength infrared?8-12?m?detectors are used in the military and civil application,especially as the international strategic resource in IR investigation,IR sky warning and missile guidance major equipment.The new generation of infrared detectors need to have the characteristics of high detectivity,multi-color,multi-band,large-area array and smaller size.In recent years,antimonide superlattice has gradually become the focus of infrared detection materials,especially the study of long-wave and very long-wave infrared bands.In particular,type ? InAs/GaSb superlattice materials have such advantages as adjustable band gap,large effective mass of electrons,and good uniformity,etc.,which indicates the better performance than HgCdTe detectors in terms of high temperature and uniformity.In recent years,Ga-free?InAs/InAsSb?superlattice infrared materials come into the field of vision.Compared to the InAs/GaSb superlattice,Ga-free?InAs/InAsSb?superlattice materials do not contain elements of Ga,which can avoid the introduction of defects associated with Ga in the forbidden band level and reduce the influence on minor carrier life.It make the carrier recombination probability decreasing greatly in the depletion layer and reduced the GR dark current derived from Shockley-Read-Hall?SRH?mechanism.The performance of infrared detector is improved effectively.This paper is devoted to the preparation of high-quality InAs/InAsSb long-wave infrared superlattice materials by molecular beam epitaxy technology on the one hand,and the preparation of long-wave infrared detectors with high quantum efficiency and high R₀A on the other hand.The PIN structure InAs/InAsSb super-lattice long-wave infrared materials was grown on GaSb substrates by molecular beam epitaxy.The effects of growth temperature,growth rate,V/III beam ratio and shutter switch sequence on crystal quality and microstructure were studied.High quality 28ML InAs/7ML InAsSb long period long wave infrared superlattice materials were prepared by Sb infiltration method.The surface of the material was extremely smooth with no defect points.The RMS roughness of the surface was about 1.3? in the range of 20×20?m2.The XRD showed that the satellite peak with more than five orders,the FWHM of the first order satellite peak is less than 80 arcsec,which indicated a high crystallization quality.By optimizing the growth conditions and parameters of the substrate heater,the128ML InAs/7ML GsSb long-wavelength infrared detector on 4 inches large GaSb substrate,the XRD showed that the satellite peak with more than six orders,the FWHM of the first order satellite peak is less than 50 arcsec,The XRD satellite peaks at the center to the edge are consistent,RMS roughness is almost unchanged,about 1.2?,it shows that the good uniformity of large area growth of InAs/GaSb superlattice materials is illustrated.InAs/InAsSb super-lattices with PIN structure long-wave infrared single detector containing 2?m active region thickness was prepared by ICP etching,passivation process.The spectral response curve showed cutoff wavelength of 50%is 8?m,the quantum efficiency was 7%,the dark current at-50mv bias was 0.01A,the zero bias impedence-area product?R₀A?was 0.07?.Cm²,and the detectivity was4.61×10¹⁰m.Hz^1/2/W.The P?MN structure InAs/GaSb superlattice long-wave a single element infrared detector.The spectral response curve showed at the cutoff wavelength of 50%is 10?m,Peak quantum efficiency is 32%,the zero bias impedence-area product?R₀A?was 0.2?.Cm²,and the blackbody detectivity was 8.77×10¹⁰m.Hz^1/2/W.