Figure 2 (IMAGE) Institute for Basic Science Caption a-b, Schematic diagrams of WS2 island on a flat a-plane sapphire surface, which has two preferred antiparallel orientations; c-d, The unidirectional alignment of WS2 island grown on vicinal a-plane sapphire with step. Credit Institute for Basic Science Usage Restrictions Attribution Required License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.