Recent work has demonstrated that the hardness of the (0001) ZnO surface is sensitive to surface charge (controlled by an applied voltage in an electrolytic cell), maximum hardness being produced by a slightly positive surface charge. The uniqueness of these findings was examined in the present work by measuring the hardness of lcub;101macr;0rcub; ZnO surfaces as a function of applied cell voltage. The results are similar to those reported earlier. A mechanism involving charge exchange between donor levels and the conduction band near moving dislocations, used to interpret the data for the (0001) surface, is applied to the results from lcub;101macr;0rcub; surfaces. To obtain agreement with the experimental results, an upward distortion of the conduction band of sim;+200 meV near basal dislocations must be assumed. This contrasts with the downward band distortion of sim;minus;50 meV near prismatic dislocations assumed to explain the earlier data.
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