Photoconductivity of Cuprous Oxide in Relation to Its Other Semiconducting Properties

It is shown that at least two of the three known peaks in the photoconductivity versus wavelength curve of ${\mathrm{Cu}}_2$O are strongly dependent on the oxygen content of the material. The peak near 600 mμ can be shifted from shorter to longer wavelengths by exposing the sample to relatively low oxygen pressures at 860°C. The peak near 800 mμ is found to increase in magnitude relative to the others under these circumstances. This is in apparent contrast to the results of previous investigators. It is further shown that both results are consistent with the values of the high temperature activation energy of the conductivity process, as well as with the change in bandgap as a function of temperature as obtained from optical absorption measurements under the assumption that ${\mathrm{Cu}}_2$O can be classified as a nonpolar semiconductor.