Scanning tunneling microscopy study of the interfacial bonding structures of Ga2O and In2O/In0.53Ga0.47As(001)

Ga"2O and In"2O oxides were deposited on In"0"."5"3Ga"0"."4"7As(001)-(4x2) surface by a high temperature effusion cell to investigate the interfacial bonding geometries and electronic structures by scanning tunneling microscopy/spectroscopy (STM/STS). At low coverage, Ga"2O molecules bond to the As atoms at the edge of the rows and preexisting Ga"2O on the surface. Annealing the Ga"2O/In"0"."5"3Ga"0"."4"7As(001)-(4x2) to 340^oC results in formation of slightly ordered islands running in the [[email protected]?10] direction and rectangle shape flat islands on the surface. At high coverage with 340^oC post-deposition annealing (PDA), Ga"2O oxides form disordered structures with the large flat terraces on the surface. Conversely, at high coverage with 380^oC PDA, In"2O on In"0"."5"3Ga"0"."4"7As(001)-(4x2) forms ordered structures running in the [110] direction. STS results show that Ga"2O oxide does not passivate the interface nor unpin the In"0"."5"3Ga"0"."4"7As(001)-(4x2) surface consistent with its inability to form monolayer ordered islands on the surface; conversely, In"2O/In"0"."5"3Ga"0"."4"7As(001)-(4x2) has an ordered monolayer coverage and is unpinned.