Structural and electronic properties of amorphous and polycrystalline In2Se3 films

Structural and electronic properties of amorphous and single-phase polycrystalline films of γ- and $\mathrm{\kappa -}{\mathrm{In}}_2{\mathrm{Se}}_3$ have been measured. The effect of deposition conditions on the film phase was studied extensively. The stable γ phase nucleates homogeneously in the film bulk and has a high resistivity, while the metastable κ phase nucleates at the film surface and has a moderate resistivity. The microstructures of polycrystalline hot-deposited and postannealed, cold-deposited γ films are quite different but their electronic properties are similar. The increase in the resistivity of amorphous ${\mathrm{In}}_2{\mathrm{Se}}_3$ films upon annealing is interpreted in terms of the replacement of In–In bonds with In–Se bonds during crystallization. Great care must be taken in the preparation of ${\mathrm{In}}_2{\mathrm{Se}}_3$ films for electrical measurements as the presence of excess chalcogen or surface oxidation may greatly affect the film properties.