Improving Photovoltage Technology (IMAGE) University of Delaware Caption Ujjwal Das, an associate scientist at the University of Delaware's Institute of Energy Conversion, examines a silicon wafer after a thin layer of sulfur - less than 5 nanometers thick - was deposited on the surface. In the background, doctoral students Robert Theisen and Isaac Lam watch a silicon wafer emerge from the atmospheric pressure vapor treatment reactor, where it was treated with hydrogen sulfide and hydrogen selenide gases. The reactor was developed at IEC. Credit Photo by Kathy F. Atkinson Usage Restrictions None License Licensed 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.