Investigation of multiple carrier effects in InN epilayers using variable magnetic field Hall measurements

Variable magnetic field Hall effect measurements were performed on InN samples grown by molecular beam epitaxy. Since mixed conduction effects due to both the presence of multiple conducting layers and sample inhomogeneity were present, standard measurements yielded only averaged results. The variable field approach allowed direct measurement of interfacial/surface conduction while also allowing determination of the bulk electrical properties. Analysis always indicated electrons with more than one value of mobility, often with a significant spread in the mobility. This suggests multiple conduction layers in the sample as well as sample inhomogeneity. Variable magnetic field analysis of a 7.5 mum thick InN sample suggests maximum mobilities greater than 4000 cm(2)/VS in "bulk" InN. The quantitative mobility spectrum analysis technique, reported here for the first time on InN, indicated a continuous and significant spread in mobility for the bulk electron, likely with sample thickness. (C) 2004 Elsevier B.V. All rights reserved.