Mid-wave InAs/GaSb superlattice barrier infrared detectors with nBnN and pBnN design

We present an investigation of optical and electrical properties of mid-wavelength infrared (MWIR) detectors based on InAs/GaSb strained layer superlattices (SLs) with nBnN and pBnN design. The temperature-dependent behavior of the bandgap was investigated on the basis of absorption measurements. A 50% cut-off wavelength of around 4.5 μm at 80 K and increase of up to 5.6 μm at 290 K was found. Values of Varshni parameters, zero temperature bandgap E0 and empirical coefficients α and β were extracted. Arrhenius plots of dark currents of nBnN and pBnN detectors were compared with the p-i-n design. Dark current density reduction in nBnN and pBnN detectors is observed in comparison to the p-i-n device. This shows a suppression of Shockley-Read-Hall (SRH) processes by means of introducing barrier architecture.