Scanning tunneling microscopy study of the interfacial bonding structures of Ga2O and In2O/In0.53Ga0.47As(0 0 1)

Ga2O and In2O oxides were deposited on In0.53Ga0.47As(0 0 1) − (4 × 2) 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, Ga2O molecules bond to the As atoms at the edge of the rows and preexisting Ga2O on the surface. Annealing the Ga2O/In0.53Ga0.47As(0 0 1) − (4 × 2) to 340 °C results in formation of slightly ordered islands running in the [1¯ 1 0] direction and rectangle shape flat islands on the surface. At high coverage with 340 °C post-deposition annealing (PDA), Ga2O oxides form disordered structures with the large flat terraces on the surface. Conversely, at high coverage with 380 °C PDA, In2O on In0.53Ga0.47As(0 0 1) − (4 × 2) forms ordered structures running in the [1 1 0] direction. STS results show that Ga2O oxide does not passivate the interface nor unpin the In0.53Ga0.47As(0 0 1) − (4 × 2) surface consistent with its inability to form monolayer ordered islands on the surface; conversely, In2O/In0.53Ga0.47As(0 0 1) − (4 × 2) has an ordered monolayer coverage and is unpinned.