Effect of interfaces and the spin-orbit band on the band gaps of InAs/GaSb superlattices beyond the standard envelope-function approximation

Abstract

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On the structural characterization of InAs/GaSb type-II superlattices: The effect of interfaces for fixed layer thicknesses

“…Nevertheless, when the spectra for each sample (B-1 to B-5) are compared, very clear red-shift in each feature is observed. It is known that the incorporation of InSb interfaces between InAs-GaSb SL layers shifts the effective bandgap to smaller energies with regard to the abrupt transition between the layers [8,14,20,[26][27][28]. The rate of shift is decreasing from samples B-1 to B-5, which is consistent with the assigned interface thicknesses for each sample (see Fig.…”

MBE growth and characterization of type-II InAs/GaSb superlattices for mid-infrared detection

“…In addition to the identification of the fundamental C 1 -HH 1 transitions, the shape of the absorption spectrum suggests the participation of several higher-energy transitions. In accordance with recent accurate calculations on InAs/GaSb SL [32], the more likely can be C 1 -LH 1 transitions (around 300 meV) and C 1 -HH 2 transitions (around 430 meV) associating the lowest electron miniband C 1 with excited holes' subbands (the first light hole LH 1 and the second heavy hole HH 2 subbands, respectively). Finally, indium contacts have been taken from the frontside and backside of the pin structure to perform photovoltaic response.…”

InAs/GaSb type-II superlattices for high performance mid-infrared detectors

“…Using short period (on the order of 40 Å ) InAs/GaSb SLs, the layer widths were systematically varied in order to adjust the band gap suitable for the 3-5 mm atmospheric window. To enhance the mid-IR design, a recently developed modified envelope function approximation (EFA) formalism [6,7] was used to predict band gap energies (E g ) and other relevant band parameters. The modified EFA calculation predicts that 26 ( A InAs/15 ( A GaSb SL with InSb-like IFs has E g around 180 meV, which is close to the 6.9 mm cut-off wavelength.…”