Bismuth oxide (Bi2O3) thin films with thickness in the range 20–160 nm have been deposited by d.c. reactive magnetron sputtering of Bi in an atmosphere Ar:O2 (1:1), onto single crystalline p‐GaSe (Cu) substrates. The optical constants, n and k, of oxide films have been determined from the analysis of the polarization ellipse of the reflected radiation from outer surface of Bi2O3/p‐GaSe structures. In the wavelength range 400–800 nm the refractive index of nanometric Bi2O3 films onto GaSe(Cu) decreases from 2.10 to 1.78 and it seen to increase at decreasing sample thickness. In order to determine the interaction mechanism between semiconducting oxide film and GaSe surface, the spectral characteristics of photocurrent through Bi2O3/p‐GaSe junction and optical absorption in the range 400–800 nm have been examined. As resulted from respective analyses, Bi2O3 film generates new valence bonds, which contribute to the increase in the density of localized states at Bi2O3/p‐GaSe (Cu) junction interface. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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The GaSxSe1‐x and GaSexTe1‐x single crystals with the composition parameter x in the range of 0 ≤ x ≤ 0.3 and 0.7 ≤ x ≤ 1 respectively have been obtained. The absorption and photoluminescence (PL) measurements have been carried out for two polarizations: E ∥ C and E ⊥ C (E is the electrical field vector of light wave and C is the crystallographic axis normal to the cleaved plane). The anisotropy of optical absorption reveals itself on the low energy wing of the n =1 free exciton band. The anisotropy coefficient increases with the temperature decrease. The edge of the absorption band is determined by direct n =1 excitons for E ⊥ C polarization and by indirect transitions at low absorption coefficient for E ∥ C polarization. The photoluminescence spectra of GaS0.2Se0.8 crystals at 78 K in E ∥ C and E ⊥ C polarizations are identical to those of GaSe. The high energy photoluminescence band is determined by the radiative emission of direct bounded excitons. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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The photoelectrical properties of p-GaSe(Cu)/n-GaAs heterojunctions obtained by optically contacting the components and by thermal evaporation of GaSe, have been studied. The rectification factor for optically contacted heterojunctions is ∼2⋅10 2 at 5 V, and the current flow is determined by diffusion mechanism. The diffusion and recombination through the interface defects mechanisms determine de current flow for heterojunctions formed by GaSe evaporation.