Midinfrared type-II InAs∕GaSb superlattice photodiodes toward room temperature operation

Abstract

We study midinfrared type-II InAs∕GaSb superlattice p-i-n photodiodes for high temperature operation. Representative samples exhibit a 3.9μm cutoff wavelength at 250K and detectivity of 4.9×1013, 1.0×1010, and 2.4×109cmHz1∕2∕W at 78, 240, and 300K, respectively. Longer-wavelength devices exhibit a 5.2μm cutoff wavelength at 240K, and detectivity of 1.3×1013 and 1.5×109cmHz1∕2∕W at 78 and 240K, respectively. The electron beam induced current technique is used to investigate the spatially varying carrier collection efficiency contribution to the quantum efficiency at different biases and temperatures. The residual doping in the i region is determined to be 6.0×1013cm−3 (n type) at 78K. The prospect of operating focal plane arrays based on the sample studied around 240K is quite promising.

Demonstration of large format mid-wavelength infrared focal plane arrays based on superlattice and BIRD detector structures

“…Growth was performed on 75 mm diameter Te-doped n-type GaSb (1 0 0) substrates. The superlattice device recipe is similar to devices reported earlier [12] and consists of a 0.5 lm Be-doped GaSb buffer layer, followed by a p-i-n superlattice 22 Å GaSb/18 Å InAs with the first 80 periods Be doped in the GaSb layers, 200 undoped periods, and the final 80 periods doped with Te in the InAs layers. The MWIR BIRD structure is an nBn structure consisting of 3 lm of nominally undoped InAsSb lattice-matched to GaSb, a 100 nm AlAsSb barrier, and a 100 nm In AsSb cap.…”

Shallow-Etch Mesa Isolation of Graded-Bandgap “W”-Structured Type II Superlattice Photodiodes

“…This state of affairs, however, has been challenged lately by the recent progress of type II superlattice (T2SL)-based devices. [1][2][3][4] First proposed by Sai-Halasz et al, 5 and implemented by Sakaki Ó 2010 U. S. Naval Research Laboratory Department of the Navy et al, 6 T2SLs exploit the type II band alignment of the InAs and Ga(In)Sb constituent layers to produce minibands with a direct energy gap (in k-space) that can be readily adjusted over a 3 lm to 30 lm cutoff wavelength range. These structures are also commonly referred to as strained-layer superlattices (SLSs), since the individual layers alternate between tensile and compressive strains that are carefully balanced over the superlattice period by judicious choices of interface bond type, layer thickness, and alloy composition.…”

Dark current mechanism of unpassivated mid wavelength type II InAs/GaSb superlattice infrared photodetector

“…Thus, InAs/GaSb T2SL infrared photodetector is regarded as an important supplement to the state-of-art HgCdTe photodetector. Recently, encouraging progress has been made for the short [1,2], mid [3][4][5][6], long [7][8][9], and very long wavelength [10][11][12] (SW, MW, LW, and VLW) infrared ranges in terms of the growth and the fabrication process. To enhance the performance, the working mechanism of the photodetector needs to be investigated, which may further promote its development and the application in industry [13,14].…”