Characterisation of n-type γ-CuCl on Si for UV optoelectronic applications

Abstract

The use of co-evaporation of ZnCl2 with CuCl in order to achieve n-type conductivity in CuCl is reported herein. Linear current-voltage (IV) characteristics in the range of ±4V have been measured using Cu-Au electrical contacts. Room temperature Hall effect measurements show some evidence of a mixed conduction mechanism. On average the samples exhibit n-type conductivity with a bulk electron carrier concentration n ~ 1 x 1016 cm-3 and Hall mobility ~ 29 cm2v-1s-1 for a CuCl sample doped with a nominal 3 mole % ZnCl2. By use of an in situ CaF2 capping layer, transmission > 90% is achieved. At room temperature a strong Z3 free excitonic emission occurs at ~385 nm using both photoluminescence and x-ray excited optical luminescence, indicating the high optical quality of the doped material.