Comparison between TiO2 thin films on InP and GaAs substrates by metalorganic chemical vapor deposition

Abstract

Titanium dioxide (TiO2) thin films have been grown on InP(100) and GaAs(100) substrates by metal organic chemical vapor deposition. The TiO2 films on InP substrates were mainly rutile phase with [110] preferred orientation while those on GaAs substrates under identical deposition conditions showed polycrystalline behavior of dominant anatase phases. Taking into account lattice mismatch consideration, three unit cells of InP(100) substrate are possibly matched with four unit cells of rutile TiO2 thin film in the TiO2[110] direction. Polycrystalline films on GaAs(100) were observed in TEM image due to large lattice misfit condition. The lattice mismatches between substrate and thin films may be one of main parameters to determine the formation of single phase of TiO2 at low deposition temperature.