A new look at ZnSe/GaAs heterostructures

Contrary to some expectations for n-ZnSe/n-GaAs heterostructures, optical and electrical measurements indicate that the GaAs side of the junction is depleted of electrons, while the ZnSe side accumulates them. The low T conductance of the n-ZnSe exhibits two-dimensional metallic behaviour: activated conduction is observed from 1.4 to 6 K, and a logarithmic variation of the conductance with temperature is observed between 14 and 45 K. A 0.75 V photovoltage under 5 mW cm-2 of white light with the GaAs negative is consistent with the theoretical predictions of Ihm and Cohen.