Scanning tunneling microscopy/spectroscopy study of atomic and electronic structures of In2O on InAs and In0.53Ga0.47As(001)-(4X2) surfaces

作者：Shen Jian^*; Chagarov Evgueni A; Feldwinn Darby L; Melitz Wilhelm; Santagata Nancy M; Kummel Andrew C; Droopad Ravi; Passlack Matthias

来源：Journal of Chemical Physics, 2010, 133(16): 164704.

DOI：10.1063/1.3497040

Interfacial bonding geometry and electronic structures of In2O on InAs and In0.53Ga0.47As(001)-(4X2) have been investigated by scanning tunneling microscopy/scanning tunneling spectroscopy (STM/STS). STM images show that the In2O forms an ordered monolayer on both InAs and InGaAs surfaces. In2O deposition on the InAs(001)-(4X2) surface does not displace any surface atoms during both room temperature deposition and postdeposition annealing. Oxygen atoms from In2O molecules bond with 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 In0.53Ga0.47As(001)-(4X2) surfaces, the Fermi level resides near the valence band maximum (VBM); however, after In2O 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 In2O bonding eliminates surface states within the bandgap and forms an unpinned interface when bonding with In0.53Ga0.47As/InP(001)-(4X2). Density function theory is used to confirm the experimental finding.

• 出版日期2010-10-28