Design And Simulation Of NBn Structure T2SL Infrared Detector

InAs/GaSb type ? superlattices are composed of thin films grown alternately with InAs and GaSb materials.Electrons(holes)tunnel between adjacent quantum wells result in the formation of minibands.The conduction band of InAs is lower than valence band of GaSb,the band alignment of InAs/GaSb type ? superlatttices result in the spatial separation of election and hole,and suppresses Auger recombination rate.The operating wavelength of InAs/GaSb type ?superlattice can be tailed from 2-30 ?m.InAs/GaSb type ? superlattices have the advantages of low Auger recombination rate,large electron effective mass and good uniformily,so InAs/GaSb type ? superlattice are widely used in infrared technology.In this work we have calculated the InAs/GaSb type ? superlattices' band structure,electrical and optical properties,and the simulation of InAs/GaSb detectors.(1)The Luttingger-Kohn 8 × 8 k·p model was used to calculate band structure of 10 ML InAs/10 ML GaSb superlattices.The 10 ML InAs/10 ML GaSb superlattices have aband gap of 0.234 eV,the cut-off wavelength is 5.3 and the peak absorption coefficient is 2500 cm-1 The result showed that 10 ML InAs/10 ML GaSb superlattices is excellent mid-wave infrared materials.(2)The dark current characteristics of InAs/GaSb type ? superlattice detectors were also studied.We designed p-i-n and nBn mid-wave InAs/GaSb superlattice.By calculating the dark current density at different doping concentrations and temperatures,at high temperatures,the dark current of the detector is depends on diffusioncurrent,and reducing the doping concentration of contact layer can reduce the dark current The nBn structure suppress the tunneling current and generation-recombination current.(3)The performance of p-i-n detector and nBn detector was compared at 120 K.The dark current density and RA of p-i-n detector are 6.62×10-5A/cm2 and 3.56×104?·cm2,respectively.and the quantum efficiency can reach 29%.The dark current density and RA of the nBn detector are 1.90×10-5 Acm-2 and 6.65×104 ?·cm2,respectively,and the quantum efficiency can reach 27%.InAs/GaSb type ? superlattices detector shown excellent infrared detection capability in mid-infrared range.