Optical constants of Ga1−xInxAsySb1−y lattice matched to GaSb (001): Experiment and modeling

Abstract

The optical constants ε(E)[=ε1(E)+iε2(E)] of two epitaxial layers of GaInAsSb/GaSb have been measured at 300 K using spectral ellipsometry in the range of 0.35–5.3 eV. The ε(E) spectra displayed distinct structures associated with critical points (CPs) at E0 (direct gap), spin-orbit split E0+Δ0 component, spin-orbit split (E1,E1+Δ1) and (E0′,E0′+Δ0′) doublets, as well as E2. The experimental data over the entire measured spectral range (after oxide removal) has been fit using the Holden model dielectric function [Holden et al., Phys. Rev. B 56, 4037 (1997)] based on the electronic energy-band structure near these CPs plus excitonic and band-to-band Coulomb-enhancement effects at E0, E0+Δ0, and the E1, E1+Δ1 doublet. In addition to evaluating the energies of these various band-to-band CPs, information about the binding energy (R1) of the two-dimensional exciton related to the E1, E1+Δ1 CPs was obtained. The value of R1 was in good agreement with effective mass/k⋅p theory. The ability to evaluate R1 has important ramifications for recent first-principles band-structure calculations which include exciton effects at E0, E1, and E2 [M. Rohlfing and S. G. Louie, Phys. Rev. Lett. 81, 2312 (1998); S. Albrecht et al., Phys. Rev. Lett. 80, 4510 (1998)]. The experimental absorption coefficients in the region of E0 were in good agreement with values obtained from a linear interpolation of the end-point materials. Our experimental results were compared to a recent evaluation and fitting (Holden model) of the optical constants of GaSb.

Sulphur passivation of GaSb, InGaAsSb and AlGaAsSb surfaces

“…The data for InGaAsSb fit well to those published by Munoz et al [18]. As for the AlGaAsSb no reference data has been published in the literature so far.…”

Numerical analysis of the short-circuit current density in GaInAsSb thermophotovoltaic diodes

“…Lines correspond to values calculated from this work and selected absorption experimental data, represented as symbols, are taken from Refs. [19][20]. Comparing the shape of the calculated absorption coefficient with the measured data in Fig.…”

Interface Intermixing in Type II InAs/GaInAsSb Quantum Wells Designed for Active Regions of Mid-Infrared-Emitting Interband Cascade Lasers

“…2 represent the theoretically predicted position of these spectra, i.e., for an ideally rectangular QW profile [23][24][25][26], which results from several composition-related effects. The primary influence on the ground state transition energy shift is attributed to the As-induced band gap change [27]. Important contributions come from strain modification in the GaIn(As)Sb layer and changes of the confinement potential; that is, in the type II system with two InAs layers, the change of the GaInAsSb energy gap entails also a change of the barrier height and the resulting coupling.…”