Gallium selenide (GaSe) films, a layered semiconductor, were prepared on silica glass substrates by electron beam deposition at various substrate temperatures (
Ts=R. T. ~500ºC). The structure, growth and optical properties of the GaSe films were studied. The unit layer of GaSe films was grown toward the two directions on silica. It is revealed that the GaSe films deposited at R. T. ~300ºC have amorphous structures, while those at 500ºC have a polycrystalline structure with their c-axis perpendicular to the substrate plane. Also it was found that the crystalline structure of the film grown at 400ºC is remarkably changed to become a c-axis parallel to the substrate plane and porous thin film. Furthermore, it was shown that the c-axis orientation of GaSe films could be controlled by the substrate temperature. The absorption edges of the GaSe films deposited at 500ºC showed a direct allowed transition with an optical gap of
Eg=2.0eV, which was in good agreement with those measured in single crystal GaSe.
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