Analysis of statistical compositional alloy fluctuations in InGaN from aberration corrected transmission electron microscopy image series

作者：Schulz T^*; Remmele T; Markurt T; Korytov M; Albrecht M

来源：Journal of Applied Physics, 2012, 112(3): 033106.

DOI：10.1063/1.4742015

We propose an approach that improves the measuring precision of lattice parameters in semiconductor alloys from high resolution transmission electron microscopy images on the unit cell scale. The method is based on the evaluation of a series of images taken under optimized imaging conditions in an aberration corrected microscope. By comparing image simulations with experimental images, we show that hardly avoidable amorphous surface layers are the main cause for the limited measuring precision. We use our approach to analyze the In distribution within a nominal In0.09Ga0.91N and In0.16Ga0.84N layer and show that both layers do not show a deviation from a random alloy. In addition, we are able to resolve local variations of the in-plane (a-lattice) and out of plane (c-lattice) parameter at the unit cell scale. These fluctuations are due to the local strain within the InGaN alloy caused by the different atomic radii of In and Ga.

• 出版日期2012-8-1