Roles of carbon in light emission of ZnO

Abstract

The origin of green light emission of ZnO has been a controversial topic. First-principles electronic structure calculations so far failed to provide useful evidence due to severe underestimation of band gap and ambiguous defect energy levels. In this work, we carried out first-principles electronic structure calculations on defected ZnO with a hybrid density functional. It was found that carbon, which cannot be completely avoided in fabricating processes, plays an important role in the commonly observed green emission, and could be the origin of green emission of ZnO. We also propose a method for the selection of emission by controlling defect types and ratio in ZnO. © 2010 American Institute of Physics.