Reversible control of the photoluminescence of ZnO occurring in the visible
range, has been achieved by application of a few volts (< 5V) to a device
consisting of nanostructured ZnO film sandwiched between Indium Tin Oxide
electrode and polyethylene oxide-lithium perchlorate, a solid polymer
electrolyte. The photoluminescence intensity shows nearly 100% modulation with
a response time less than 30 seconds, when the bias is applied at the
electrolyte-electrode. A model is proposed for the observed effect that is
based on defect states of ZnO and the band bending at the ZnO-electrolyte
interface that can be changed by the applied bias
