OPTICAL-PROPERTIES OF ZN3P2 THIN-FILMS

Polycrystalline and amorphous thin films of Zn3P2 were deposited on SiO2 and Al2O3 oriented crystal substrates by direct evaporation from a quartz crucible at temperatures of 820-970 K. The thickness of the layers varied from 0.16 to 3 mum. Structural studies by the X-ray diffraction method indicated good quality of the samples. Transmission and reflection measurements were carried out in the wide energy range 1-5 eV. The absorption coefficient and reflectivity spectra, taking into account strong light interference, were calculated. In transmission measurements, optical transitions in the GAMMA points (1.5 eV) as well as in the L points (2.7 eV) of the Brillouin zone were observed; in reflection measurements, transitions in the L and X (4.6 eV) points were observed. The obtained optical spectra of thin films were compared with those for monocrystals.