Hs. Soliman, OPTICAL-PROPERTIES OF AGGASE2 POLYCRYSTALLINE FILMS PREPARED BY FLASHEVAPORATION, Journal of physics. D, Applied physics, 28(4), 1995, pp. 764-769
Structural studies on AgGaSe2 films prepared in vacuum of 10(-4) Pa on
to glass or quartz substrates by a flash evaporation technique and ann
ealed at 573 K for 2 h show that these films were polycrystalline and
exhibited tetragonal chalcopyrite structure with a strong (112) orient
ation with a = 0.599 nm, c = 1.089 nm and (c/a) = 1.816. The optical c
onstants (the refractive index n, the absorption index k and the absor
ption coefficient alpha) of polycrystalline AgGaSe2 films were determi
ned from spectrophotometric measurements of the transmittance and refl
ectance carried out at normal incidence in the wavelength range 500-20
00 nm. Graphical representations of surface and volume energy loss fun
ctions as well as the real optical conductivity as a function of photo
n energy show the existence of three possible optical transitions corr
esponding to 1.79, 1.95 and 2.2 eV respectively.