Long wavelength infrared detector based on Type-II InAs/GaSb superlattice

A 12.5 μm long wavelength infrared detector based on InAs/GaSb Type-Ⅱ superlattice was presented in this work.Superlattice materials were grown on GaSb substrates using MBE technology.Absorber structure for long wavelength detector was designed to be 15ML(InAs)/7ML(GaSb).The detector used a PBIN multiple heterostructures to decrease the dark current.The dark current I-V curve,responsivity spectra and blackbody current responsivity were measured at 77 K.At this temperature,RmaxA product was 2.5 Ωcm2 for the device with a photo sensitive area of 100 μm× 100μm.At zero bias,a current responsivity of 1.29 A/W was measured for the detector,which correspond to a blackbody detectivity of 2.1×109 cmHz1/2/W.Quantum efficiency at 11 μm was measured to be 14.3%.Dark current characteristics were simulated with four kinds of probable transport mechanisms.The results showed that the dominated dark current of the detector is Generation-Recombination current.