Lateral diffusion of minority carriers in nBn based type-II InAs/GaSb strained layer superlattice detectors

Abstract

We report on the investigation of lateral diffusion of minority carriers in nBn based InAs/GaSb strained layer superlattice photodetectors. Values of diffusion length of minority carriers were extracted from temperature dependent I-V measurements. The behavior of diffusion length as a function of applied bias, temperature, and composition of the barrier layer and the values ranging by two orders of magnitude from 77 to 250 K at the same value of applied bias were investigated. The obtained results suggest that at this point the lateral diffusion current could be the limiting factor of the MWIR nBn detector performance at low (<150 K) temperatures.

InAs/GaSb superlattices for advanced infrared focal plane arrays

“…Investigations on lateral carrier diffusion can be found in Ref. [3]. On top of a 500 nm AlGaAsSb lattice matched buffer layer, 1500 nm of GaSb:Be (1 Â 10 18 cm À3 ) were followed by the active SL region terminated by 20 nm of InAs:Si (5 Â 10 17 cm À3 ).…”

Passivation of long-wave infrared InAs/GaSb strained layer superlattice detectors

“…An elegant approach to the solution of the surface leakage current problem is the recently proposed nBn detector design [13]. The buried device architecture utilized in nBn SLS devices effectively precludes surface currents but is limited by the lateral diffusion length, which can be very large [14].…”

“…Photodetectors operating in the long-wave infrared (LWIR, [8][9][10][11][12][13][14] lm) spectral band could be potentially useful for a wide variety of applications such as meteorology, astrophysical imaging, missile detection and tracking, and satellite based surveillance. The technologies currently dominating those applications in this wavelength range are based on interband Mercury-CadmiumTelluride (MCT) and intersubband quantum well infrared (QWIP) detectors.…”

Barrier infrared detectors

“…12 [5,43]. Under forward bias (defined as negative voltage applied on the top contact), the photocarriers are collected from the SL ab− sorber with l 2 cutoff wavelength.…”