Molecular-beam-epitaxial growth and characterization of In2Te3

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Abstract
We report studies of the molecular‐beam‐epitaxial growth of In2Te3. The unique structure of In2Te3, with 1/3 of the In sublattice sites vacant, is of fundamental interest for molecular‐beam‐epitaxial growth dynamics. We show that thin‐film (500–7000 Å) single‐crystal In2Te3 can be grown successfully on InSb(100) homoepitaxial layers at substrate temperatures of 300–350 °C and Te/In flux ratios of 3/2 to 5/2. Epitaxy has been monitored by reflection high‐energy electron diffraction and the stoichiometry of the grown layers assessed by Auger spectroscopy and energy dispersive x‐ray analysis. Raman studies of the layers are presented and compared with a bulk In2Te3 standard. Crystal structure has been determined by x‐ray diffraction using Weissenburg and oscillation photographs, confirming that the layers have a fcc crystal structure with a lattice parameter of 18.50 Å, in excellent agreement with the bulk value. Band‐gap measurements have been performed on the layers by photoreflectance. We report a value for the α‐In2Te3 band gap of 1.19 and 1.31 eV at 300 and 77 K, respectively. Molecular‐beam‐epitaxial growth of InSb and CdTe on epitaxial In2Te3 films for fabrication of InSb/In2Te3/InSb and InSb/In2Te3/CdTe multilayers has been studied. Auger depth profiling of the resulting layers shows severe intermixing into the In2Te3. These results are supported by thermodynamic considerations of the InSb‐In2Te3 interface.