Materials growth and band offset determination of Al_2O_3/In_(0.15)Ga_(0.85)Sb/GaSb/ GaAs heterostructure grown by metalorganic chemical vapor deposition

摘要

The ternary In_xGa_(1-x)Sb epilayers grown on GaAs substrates by metalorganic chemical vapor deposition using a GaSb buffer layer have been demonstrated. High-resolution transmission electron microscopy micrographs illustrate an entirely relaxed GaSb buffer grown by the interfacial misfit dislocation growth mode. A high quality In_(0.15)Ga_(0.85)Sb epilayer was obtained on the GaSb surface with the very low threading dislocation densities (～8.0 × 10~6 cm~(-2)) and the surface roughness was 0.87 nm. The indium content of the In_xGa_(1-x)Sb epilayer depends significantly on the growth temperature and approaches to a saturated value of 15% when the growth temperature was above 580 ℃. Based on the X-ray photoelectron spectroscopy analyses, the valence band offset and the conduction band offset of Al_2O_3 with the In_(0.15)Ga_(0.85)Sb/GaSb/GaAs heterostructure are 3.26eV and 2.91 eV, respectively. In addition, from the O1s energy-loss spectrum analysis, the band gap of Al_2O_3 is found to be ～6.78 ± 0.05 eV.