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-2of white light with the GaAs negative is consistent with the theoretical predictions of Ihm and Cohen.
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