Photoconductivity Spectral Response and Lattice Parameters of Hexagonal ZnSe

The hexagonal modification of ZnSe single crystals has been observed. The crystals were grown by the sublimation method. The lattice parameters are found to be a0 = 4.003±0.001 Å and c0 = 6.540±0.003 Å. The photoconductivity peaks observed in the spectral response curves at room temperature reflect the band symmetries of the wurtzite structure and obey the group theoretical selection rules. From the position of the photoconductivity maxima for E ⊥ C, the band gap energy at room temperature is estimated to be 2.795 eV.