Visualizing Interfacial Structure at Non-Common-Atom Heterojunctions with Cross-Sectional Scanning Tunneling Microscopy

Abstract

We describe how cross-sectional scanning tunneling microscopy (STM) may be used to image the interfacial bonding across the nearly lattice-matched, non-common-atom GaSb/InAs heterojunction with atomic-scale precision. The method, which takes advantage of the length difference between interfacial and bulk bonds, appears equally applicable to AlSb/InAs and suggests how one might recover the complete structure of either heterojunction from atomic-resolution STM data.

Effect of growth temperature on surface morphology and structure of InAs/GaSb superlattices grown by metalorganic chemical vapor deposition

“…Previous report has shown the arsenic-for-antimony and indiumfor-gallium exchanges by using cross-sectional scanning tunneling microscopy [11]. In MBE growth of InAs/GaSb SLs, this problem may be partially solved by utilizing low growth temperature, typically about 400 1C [11]. However, a higher growth temperature is preferred in the MOCVD growth of InAs/GaSb SLs, due to the high decomposition temperature of the precursors.…”

“…The difficulties arise not only from the lattice mismatch between InAs and GaSb [9,10], but also from the special V-group precursor of trimethylantimony (TMSb) and interdiffusion near the interfaces where no common atoms exist. Previous report has shown the arsenic-for-antimony and indiumfor-gallium exchanges by using cross-sectional scanning tunneling microscopy [11]. In MBE growth of InAs/GaSb SLs, this problem may be partially solved by utilizing low growth temperature, typically about 400 1C [11].…”

Optimization of InAs/GaSb type-II superlattice interfaces for long-wave (∼8μm) infrared detection

“…In InAs/GaSb SLS, two types of interfaces can be grown along the [0 0 1] growth direction, the ''InSb-like'' or ''GaAs-like'' interface. The existence of these interfaces have been clearly shown by other research groups using scanning tunneling microscopy [10,11]. Since the lattice constant of InSb (GaAs) is much larger (smaller) than that of the GaSb substrate, insertion of a few monolayers (MLs) of these materials leads to a large compressive (tensile) strain, thereby dramatically changing the structural, optical and electrical properties of the SLS.…”

Investigation of InAs/GaSb-based superlattices by diffraction methods

“…Most common imperfections are related to the interface roughness and atomic intermixing during growth (see e.g. [7,8]). In this paper, we handle some metrology issues related to the structural characterization of GaSb/InAs superlattices with a focus on their strain state, the thicknesses of individual sub-layers and interface quality.…”