Scanning tunneling microscopy/spectroscopy study of atomic and electronic structures of In2O on InAs and In0.53Ga0.47As(001)-(4×2) surfaces

Jian Shen, Evgueni A. Chagarov, Darby L. Feldwinn, Wilhelm Melitz, Nancy M. Santagata, Andrew C. Kummel, Ravi Droopad, Matthias Passlack
2010 Journal of Chemical Physics  
Interfacial bonding geometry and electronic structures of In 2 O on InAs and In 0.53 Ga 0.47 As͑001͒-͑4 ϫ 2͒ have been investigated by scanning tunneling microscopy/scanning tunneling spectroscopy ͑STM/STS͒. STM images show that the In 2 O forms an ordered monolayer on both InAs and InGaAs surfaces. In 2 O deposition on the InAs͑001͒-͑4 ϫ 2͒ surface does not displace any surface atoms during both room temperature deposition and postdeposition annealing. Oxygen atoms from In 2 O molecules bond
more » ... th trough In/Ga atoms on the surface to form a new layer of O-In/Ga bonds, which restore many of the strained trough In/Ga atoms into more bulklike tetrahedral sp 3 bonding environments. STS reveals that for both p-type and n-type clean In 0.53 Ga 0.47 As͑001͒-͑4 ϫ 2͒ surfaces, the Fermi level resides near the valence band maximum ͑VBM͒; however, after In 2 O deposition and postdeposition annealings, the Fermi level position is close to the VBM for p-type samples and close to the conduction band minimum for n-type samples. This result indicates that In 2 O bonding eliminates surface states within the bandgap and forms an unpinned interface when bonding with In 0.53 Ga 0.47 As/ InP͑001͒-͑4 ϫ 2͒. Density function theory is used to confirm the experimental finding.
doi:10.1063/1.3497040 pmid:21033816 fatcat:pfuzzj7tr5asrjlazhzbfj3xge