Bonding Geometries at the In2O and SiO/III-V Semiconductor Interface

Abstract

Oxide monolayers and submonolayers formed by vapor depositon of In2O and SiO oxides on InAs(001)-(4x2) were studied by scanning tunneling microscopy (STM). At low coverage, In2O molecules bond to the edges of the rows and most likely form new In-As bonds to the surface without any disruption of the clean surface structure. Annealing the In2O/InAs(001)-(4x2) surface to 380åC results in formation of flat ordered monolayer rectangular islands. The annealed In2O no longer bonds with just the As atoms at the edge of row but also forms new O-In bonds in the trough. SiO chemisorption on InAs(001)-(4x2) is completely different than In2O chemisorption. At room temperature, even at low coverage SiO adsorbates bond to themselves and form nanoclusters. For SiO/InA(001)-(4x2) post-deposition annealing (PDA) does not disperse the nanoclusters into flat islands. Both In2O and SiO depositions on InAs(001)-(4x2) surface do not displace surface atoms during both room temperature deposition and PDA.