Enhancement of the photocurrent in ultraviolet photodetectors fabricated utilizing hybrid polymer-ZnO quantum dot nanocomposites due to an embedded graphene layer

Transmission electron microscopy images of ultraviolet (UV) photodetectors based on hybrid polymer-ZnO quantum dots (QDs) incorporating graphene showed that the ZnO QDs were distributed at the circumference of the surface of the poly-N-vinylcarbazole (PVK) layer and that the graphene layer were attached to the surface of the ZnO QDs and PVK layer. Current-voltage (I-V) measurements on the UV photodetectors showed that the ratio of the photocurrent to the dark current was approximately 10(8) and that the photocurrent was significantly enhanced by using the graphene layer. The carrier transport mechanisms of the UV photodetectors are described on the basis of the I-V results. (C) 2010 Elsevier B.V. All rights reserved.This work was supported by the Korea Science and Engineering Foundation (KOSEF) grant funded by the Korea Government (MEST) (No. R0A-2007-000-20044-0)