Surface conductivity of epitaxial InN

The electron accumulation at the surface of oxidised InN layers has been investigated by resistance measurements and simultaneous sputtering by Ar+ ions under gracing incidence. The removal of InN decreases continuously the cross section of the conductive InN layer on the insulating substrate. From the measurements the depth profile of the free electron concentration was derived and an excess sheet carrier density at the surface of 2.2 x 1013 cm-2 was estimated. The agreement of the Auger oxygen depth profiles and the free electron concentration profile motivates the conclusion that oxygen is responsible for the high surface conductivity of InN layers exposed to air. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)