Type-II InAs/GaSb strained layer superlattices grown on GaSb (111)B substrate

Abstract

In this paper, the authors report on the growth of InAs/GaSb type-II strained layer superlattice (T2SL) material on (111)B GaSb substrates. Both substrate temperature and V/III beam equivalent pressure ratio were varied to optimize the crystalline and optical quality of the T2SL material. Midwave infrared (λ100% cut-off ∼ 5.6 μm at 295 K) InAs/GaSb T2SL detectors were then grown on the same substrate orientation. After detailed radiometric characterization, the authors have measured, at 295 K and 4 μm, a dark current density of 0.53 A/cm2 (at −50 mV) and a Johnson noise limited specific detectivity (D*) of 8.5 × 109 Jones, which are superior values to the state-of-the-art T2SL detectors grown on conventional GaSb (100) substrates and operating in a similar wavelength range.

Inductively coupled CH 4 /H 2 plasma etching process for mesa delineation of InAs/GaSb type‐II superlattice pixels

“…5 shows the bias dependent dark current densities for a 400 μm × 400 μm T2SL photodiode in the VADA structure measured at different temperatures. At 70 K, the dark current density was found to be 0.11 A/cm 2 at an applied reverse voltage of 0.2 V which is an order of magnitude higher than the reported result [17]. However, at room temperature, the dark current was found to be very high with nearly non-rectifying characteristics and hence the data are not presented here.…”

InAs/GaSb Type-II Superlattice Detectors

“…Another approach for the realization of high performance T2SL sensors is growth of T2SL structures on high-index plane GaSb [171]. The thickness of the T2SL detector grown on the GaSb (111) substrate is reduced due to the natural difference of lattice parameters in the (111) and (100) directions, whereas heavy hole confinement is increased by a factor of three [172].…”

Many-body perturbation theory study of type-II InAs/GaSb superlattices within the GW approximation

“…The total atoms per unit cell used in each material are 46, 54, 68, 76 and 80, respectively. Care was taken to simulate the structures as close as possible to the experimental growth condition in our laboratories and other reports in the literature [24][25][26][27]. Figure 1 shows the unit cell of an (n, m) T2SL, along with the type-II broken-gap alignment of its constituent materials.…”