Illustration (image) Bielefeld University Share Print E-Mail Caption When a control voltage is applied to graphene, the frequency conversion of the current can be controlled. Credit Image: Juniks, Dresden, CC-BY Usage Restrictions The image may only be used with appropriate caption or credit. Share Print E-Mail 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.