“…If this value is compared with experimental data for the absorption coefficient spectrum of CuInSe, NEUMANN et al 1982;TUTTLE et al;VARELA et al) it follows that the corresponding photon energy must be very close to the gap energy, kv,,, 6 E , + 0.01 eV. Furthermore it is evident from all absorption studies on thin polycrystalline films NEUMANN et al 1982;TUTTLE et al) that at photon energies above 1.4 eV the absorption coeficient increases monotonically and slowly up to about 2.5 eV and at a slightly faster rate at higher photon energies. Thus, since the spectral dependence of the photoconductivity at hv > hv,,, is given by relation (4) we should expect that do exhibits a continuous and structureless decrease up to about 2.5 eV followed by a slightly faster decrease at kv > 2.5 eV.…”