Interface investigation of InAs/GaSb type II superlattice for long wavelength infrared photodetectors

Abstract A modified method based on the conventional migration-enhanced epitaxy (CMEE) for the growth of InSb layer at the GaSb-on-InAs interface of long wavelength InAs/GaSb superlattice (SL) was studied. The surface morphologies and structural properties of the SLs with two different growth methods of InSb layer were compared. The atomic force microscope (AFM) morphologies showed better surface of the MMEE samples with InSb layer at and beyond 1.0ML. The high resolution X-ray diffraction (HRXRD) revealed that the MMME method was of more efficient strain compensation. At 77K, the PIN structure SL detector grown by the MMEE method demonstrated a cutoff wavelength of 10.7μm and showed dark current density of 1.13×10-4A/cm2 at -50mV and a R0A of 37.9Ω.cm2.