Band engineered HOT midwave infrared detectors based on type-II InAs/GaSb strained layer superlattices

We report on heterostructure bandgap engineered midwave infrared photodetectors based on type-II InAs/GaSb strained layer superlattices with high operating temperatures. Bandgap and bandoffset tunability of antimonide based systems have been used to realize photodiodes and photoconductors. A unipolar barrier photodiode, pBiBn, and an interband cascade photovoltaic detector have been demonstrated with a 100% cutoff wavelength of 5 μm at 77 K. The pBiBn detector demonstrated operation up to room temperature and the cascade detector up to 420 K. A dark current density of 1.6 × 10−7 A/cm2 and 3.6 × 10−7 A/cm−2 was measured for the pBiBn and interband cascade detector, respectively, at 80 K. A responsivity of 1.3 A/W and 0.17 A/W was observed at −30 mV and −5 mV of applied bias for pBiBn and cascade detector, respectively, at 77 K. The experimental results have been explained by correlating them with the operation of the devices.