Open AccessUpside-down InAs/InAs1-xSbx type-II superlattice-based nBn mid-infrared photodetectors with an AlGaAsSb quaternary alloy barrier
Author(s) -
Gongrong Deng,
Xiu-Neng Song,
Mingguo Fan,
Tingting Xiao,
Zhibing Luo,
Chen Niu,
Wenyun Yang,
Yiyun Zhang
Publication year - 2020
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.387297
Subject(s) - responsivity , photodetector , superlattice , materials science , specific detectivity , dark current , optoelectronics , infrared , indium arsenide , quantum efficiency , alloy , infrared detector , optics , gallium arsenide , physics , composite material
Ga-free InAs/InAsSb type-II superlattices (T2SLs) are emerging as candidate materials for high temperature operation of mid-infrared photodetectors, which are critical for infrared technology with an aim to provide low-cost and compact detection systems. In this work, by utilizing upside-down device structure, a closely lattice-matched Al 0.83 Ga 0.17 AsSb quaternary alloy as electron barrier was pre-grown before the growth of InAs/InAsSb T2SLs absorber in a nBn device. Based on this design, we have demonstrated 5-µm cut-off mid-wavelength infrared (MWIR) photodetectors that exhibited a dark current density of 1.55 × 10 -4 A/cm 2 at an operation bias 400mV at 150K. A saturated quantum efficiency at ∼4.0 µm reaches 37.5% with a 2 µm absorber and the peak responsivity reaches 1.2 A/W, which yields a peak specific detectivity as high as ∼1.82 × 10 11 cm·H z 1/2 /W at a forward bias of 400mV.