Quantifying stoichiometry of mixed-cation-anion III-V semiconductor interfaces at atomic resolution

Abstract

Employing the focal-series reconstruction technique in high-resolution transmission electron microscopy, we obtained true atomic resolution images of interfacial disorder within cation and anion sublattices across interfaces in an InGaSb∕InAs heterostructure. This enabled independent quantitative mapping of changes in the In–Ga and As–Sb contents across interfacial regions ∼0.6nm in width. A comparison of the cation and anion sublattice images revealed that intermixing at the InGaSb-on-InAs interface is confined to the In–Ga sublattice. Also, atomic scale roughness within the As–Sb sublattice of the InAs-on-InGaSb interface was discerned. This approach is general, permitting atomic-scale compositional analysis of heterointerfaces with two species per sublattice.

Interface properties of (Ga,In)(N,As) and (Ga,In)(As,Sb) materials systems grown by molecular beam epitaxy

“…These results are in agreement with those reported by Mahalingam et al [21] in one of the few papers on the chemical characterization of the InAs/GaSb SPSs.…”

Interfacial intermixing in InAs/GaSb short-period-superlattices grown by molecular beam epitaxy

“…Using different techniques, it was found that the interface InAs-on-GaSb is extended while the interface GaSb-on-InAs is more abrupt. [3][4][5][6] This arises from the exchange reactions between As and Sb 7 as well as the incorporation of Sb into InAs promoted by the strong segregation tendency of Sb. 8 While most of the studies focus on the interfacial roughness ͑i.e., steps and islands͒, little is known about the interfacial intermixing ͑i.e., composition profile͒.…”

“…An alternative approach is then required. Mahalingam et al 6 determined the change in composition across a 17 ML InAs/6 ML In 0.25 Ga 0.75 Sb SL structure using sophisticated reconstruction of the exit wave function in HRTEM. More recently, preliminary composition profiles from 15 ML InAs/17 ML GaSb SLs obtained using atom probe tomography have been presented, 10 where complicated data reconstruction analysis is essential for a correct interpretation of the results.…”

Use of Sb spray for improved performance of InAs/GaAs quantum dots for novel photovoltaic structures

“…4) is shown. It is assumed that the Sb does not penetrate the InAs, or is minimal [19,20], though it must be pointed out that Sb penetration of InAs QDs has been reported [21], though in that case it was a layer of GaSb grown directly on the QDs and not surface adsorbed Sb, as in our case. The thin graded GaAsSb immediately adjacent to the QDs sees a spike in the conduction band (CB) edge as well as a rounding in the valence band (VB) edge around the QD/cap interface.…”

“…The increase in QD emission intensity has been ascribed to a lowering of the coalescence of the InAs QDs (and therefore a greater number of coherent QDs) due to the surfactant effect of Sb [17]; however, there is no discernible improvement in the FWHM for our samples, suggesting the size distribution is not affected by the Sb spray. This lack of significant improvement in FWHM can be understood by the Sb not penetrating the InAs [19,20] and so not significantly affecting the surface diffusion of In adatoms during the InAs growth stage.…”