InAs/InAsSb strain balanced superlattices for optical detectors: Material properties and energy band simulations

Abstract

InAsSb/InAs type II strain balanced superlattices lattice matched to GaSb have recently been proposed as an alternative to InAs/(In)GaSb short period superlattices for mid- to long infrared photodetectors. Photoluminescence data at 4 K of OMVPE grown InAsSb (multi-) quantum wells in an InAs matrix on InAs and GaSb substrates is presented for Sb compositions between 4% and 27%. The measured transition energies are simulated with a self-consistent Poisson and Schroedinger equation solver that includes strain and band-offsets. The fitted parameters are then used to predict the type II transition energies of InAsSb/InAs strain balanced superlattice absorber stacks at 77 K for different compositions and periods. The optical matrix element was calculated and compared with InAs/(In)GaSb superlattices. The InAsSb/InAs structures can be designed with higher or equal matrix elements for longer periods. Finally, the initial optical response data of an unoptimized strain balanced InAs0.79Sb0.21/InAs detector with a 40 nm period are shown. Its cutoff wavelength is 0.15 eV (8.5 μm), in good agreement with the predicted type II transition energy of 0.17 eV.

InAs/GaSb superlattice pin photodiode: choice of the SL period to enhance the temperature operation in the MWIR domain

“…Indeed, the residual doping is one decade higher when the GaSb content in the SL period increases from 36% to 65%, proving that the main source of residual doping in the InAs/Gab SL is due to GaSb material. This remark on the residual doping of SL structure can be correlated with the recent studies performed on "GaSb-free" InAsSb/InAs SL structures 20 . Generally, improved material properties, such as carrier lifetime, are obtained for "GaSb-free" structures 21 .…”

Progress in Infrared Photodetectors Since 2000

“…Gallium-free versions also exist, using the same InAs layer for electron capture, but using an InAsSb for the hole capture. Use of InAsSb layers in place of GaSb would allow for longer wavelength absorption, but to this point research has been limited to characterization of superlattices comprised of these materials as opposed to fabrication of functioning photodetectors [137–139]. Due to the structure of SLS, dark currents tend to be fairly low for these devices.…”

Digital model for X-ray diffraction with application to composition and strain determination in strained InAs/GaSb superlattices

“…For example, superlattices made of metals, metal oxides, and compound semiconductors have demonstrated unique functionalities such as protective coating, 1,2 magnetoresistence, 3-5 superconductivity, 6,7 IR-detection, [8][9][10] and quantum cascade lasers. 11,12 The desired physical properties are achieved through designs of the superlattice structures using layer thickness, [13][14][15] composition, 16,17 strain, 8,18 and interfaces. [19][20][21] The performances of devices built upon superlattices can be highly sensitive to the quality of superlattices formed during growth.…”