Figure 1 (IMAGE) Institute for Basic Science Caption a, Single-crystal WS2; b, Sapphire wafer used in industry is a single-crystal; c, Experimental images about the WS2 films on sapphire wafer after O2 etching. 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.