ANOMALOUS PHOTO-VOLTAIC EFFECT IN THE ABSORPTION TAIL OF CUBIC ZNSE

An anomalous but weak photovoltaic effect has been observed in cubic crystals of zinc selenide in the spectral range of the absorption tail. Parallelepiped samples exhibit twinned and birefringent strips, and a photovoltage of about 100 mV with reversal of sign appears when the electrodes are parallel to the twinning planes. A study of the optical absorption tail shows that the absorption coefficient is different from a twinned area and an untwinned area. It is attempted to explained qualitatively the experimental results with a model derived from that of Cutter and Woods (1975) when the wavelength is greater than the optical absorption threshold.