Modifications of the electronic structure of GaSb surface by chalcogen atoms: S, Se, and Te

Abstract

Modifications to the electronic properties and chemical structures of the GaSb surface using the chalcogen atoms S, Se, and Te were investigated theoretically and experimentally. A self-consistent density-functional theory study indicates that an adsorption of a full monolayer coverage of chalcogen atoms on a Ga-terminated surface reduces the density of gap region states significantly. A greater photoluminescence enhancement was observed from GaSb samples treated by chalcogenide (Na 2 S, Na 2 Se, or Na 2 Te) in a nonaqueous than in an aqueous passivation medium. X-ray photoelectron spectroscopy reveals a Ga-rich surface after a nonaqueous passivation, with sulfidization providing a higher concentration of Ga͑Sb͒-chalcogen bonds than does a passivation with Na 2 Se or Na 2 Te. The uptake of chalcogen during the passivation is accompanied by the loss of surface antimony. The formation of Sb-X(X = S, Se, or Te) bonds competes with X displacing surface Sb, which dominates Se or Te incorporation in the GaSb surface lattice. The passivation kinetics was analyzed on basis of a single precursor-mediated coverage-dependent chemisorption proces.

Density Functional Theory Study of Ligand Binding on CdSe (0001), (0001̄), and (112̄0) Single Crystal Relaxed and Reconstructed Surfaces: Implications for Nanocrystalline Growth

“…The first two parameters are directly computed in this work by using density functional theory (DFT-GGA), a method that has been utilized extensively in the past to study reactive processes on semiconductor surfaces. [20][21][22] The third parameter is described qualitatively by using heuristic arguments to relate the steric behavior of a model ligand to its actual counterpart.…”

“…And finally steric hindrance determines both the packing efficiency of ligands on the surface and the ability of the ligand to sterically block binding sites for growth species adsorption. The first two parameters are directly computed in this work by using density functional theory (DFT-GGA), a method that has been utilized extensively in the past to study reactive processes on semiconductor surfaces. − The third parameter is described qualitatively by using heuristic arguments to relate the steric behavior of a model ligand to its actual counterpart.…”

Passivation techniques for InAs/GaSb strained layer superlattice detectors

“…Liu et al. , , investigated non‐aqueous versus aqueous‐based passivation of GaSb (100) surfaces. A non‐aqueous passivation solution contained a sodium sulfide in anhydrous benzene.…”

Study of Short- and Long-Term Effectiveness of Ammonium Sulfide as Surface Passivation for InAs/GaSb Superlattices Using X-Ray Photoelectron Spectroscopy

“…[4][5][6][7][8][9] It was shown that sulfidization with ammonium sulfide [(NH 4 ) 2 S] solutions effectively improves surface properties of InAs and GaSb. 4,5 The passivation mechanism in this case can be described as follows: first, (NH 4 ) 2 S effectively removes native oxides with minimal surface etching, and then a covalently bonded sulfur layer is created.…”