  Structural and electronic properties of amorphous and single-phase
polycrystalline films of gamma- and kappa-In2Se3 have been measured. The stable
gamma phase nucleates homogeneously in the film bulk and has a high
resistivity, while the metastable kappa phase nucleates at the film surface and
has a moderate resistivity. The microstructures of hot-deposited and
post-annealed cold-deposited gamma films are quite different but the electronic
properties are similar. The increase in the resistivity of amorphous In2Se3
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 In2Se3 films for electrical measurements as the presence of
excess chalcogen or surface oxidation may greatly affect the film properties.
