Abstract:

Amorphous gallium selenide (a-GaSe) semiconductor nanoparticle thin films were deposited onto well cleaned glass substrates by inert gas condensation (IGC) technique under a vacuum of 400 × 10⁻⁶ Pa (3 × 10⁻⁶ Torr). The films were characterized by different structural and optical techniques, including X-ray diffraction, field emission scanning electron microscopy (FESEM), field emission transmission electron microscopy (FETEM), UV–visible absorption spectroscopy and I–V measurements. The particle size and size distribution were determined by TEM images which show the presence of spherical particles in the range of 5–50 nm in size. SEM images indicate that the a-GaSe film grown on glass substrate is almost smooth and dense. The optical properties of a-GaSe nanoparticle thin films were determined by optical absorption spectra. The optical bandgap of the film was estimated to be 2.19 eV and the transitions are allowed direct type. The electrical conductivity of the deposited films has been studied as a function of temperature. In the higher temperature range the dominance of thermally activated band conduction was observed; whereas in the low temperature range the hopping conduction in the band tails of localized states was found to be dominated.

Key words: a-GaSe, Nanoparticles, Thin film, Optical bandgap, Electrical conductivity