Surface barriers on ZnSe and ZnO

Abstract

We report measurements of surface barrier heights of several metals on vacuum cleaved ZnSe and ZnO surfaces, indicating that both of these materials behave as expected for materials without surface states. Samples were prepared by cleavage in a vacuum in the stream of evaporating metal, thus insuring a clean interface. Barrier heights were measured using the photoresponse technique on the ZnSe and for the higher barriers on the ZnO, and by analysis of the [-V characteristic for the lower barriers on ZnO (Cu, In, Al, Ti). The detailed procedure has been described previously [1]. The results of this study are shown in fig. 1, together with the values for ZnS taken from Aven and Mead [2]. The probable errors are greater for the lower barriers, in some cases it being only possible to give an upper limit (as indicated by the bars). For the higher barriers the probable error is less than 0.1 eV.

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