Photoelectric properties of cuprous oxide

Abstract

The effects of transient and steady−state illumination on the electrical properties of single−crystal cuprous oxide have been investigated in the temperature range from 230 to −20 °C. For samples equilibrated well within the region of Cu2O stability, conduction was governed by an acceptor level at 0.4 eV above the valence band as determined from the temperature dependence of the Hall effect. The presence of two minority carrier trapping levels was also established and trapping parameters were determined from an analysis of the transient photoconductivity. The 0.4−eV acceptor level was also found to be present in a sample equilibrated under conditions placing its composition in a region near the CuO−Cu2O phase boundary. For this sample, however, only a single deeper trapping level was observed. A third type of sample, equilibrated under conditions which placed its composition in a region near the Cu−Cu2O phase boundary, was characterized by both a high hole density and a high mobility with an acceptor level energy of 0.16 eV. Also, the presence of two effects, the thermal quenching of the steady−state photoconductivity and its nonlinear dependence on light intensity, were shown to be consistent with the presence of deep traps in this material.