Amorphous state of thin films of the Ga-Te and In-Te systems

The structure and physical properties of amorphous films of the Ga-Te and In-Te systems obtained by thermal deposition in vacuum were studied as a function of the Te content in the range between 40 and 80 at.% Te. Except for In-Te films containing less than 42 at.% Te, all thin films deposited on substrates of temperatures less than 50 C were found to be amorphous, regardless of the deposition conditions. It is shown that the maximal forbidden bandwidth in amorphous films is smaller than in crystalline films and that the Fermi level is situated close to the center of the forbidden band, but closer to the valence band.