Electron barrier study of mid-wave infrared interband cascade photodetectors

In this paper, we report our experimental investigation on the influence of electron barrier (eB) in mid-infrared interband cascade photodetectors. Even though earlier theoretical projection indicates that an eB with 2-pairs GaSb/AlSb quantum wells (QWs) is sufficient to block electrons direct tunneling between stages, our experimental results show that a thicker (with 6-pairs of GaSb/AlSb QWs) electron barrier could significantly reduce the device dark current, with little influence on the optical performance. The 5-stage devices have demonstrated a dark current density of 1.10 x 10(-7) A/cm(2) (at -5mV) and a Johnson-limited D* of 1.81 x 10(11) cmHz(1/2)/W (at 3.8 mu m) at 150 K, respectively. (C) 2013 AIP Publishing LLC.