Light Activates Reaction (IMAGE) Princeton University, Engineering School Caption Researchers used ultraviolet light to excite molecules in a semiconductor, triggering reactions that split up and activated a dopant Credit Jing Wang and Xin Lin Usage Restrictions non-commercial use 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.