Sb-doped p-ZnO quantum dots: Templates for ZnO nanorods homojunction white light-emitting diodes by low-temperature solution process

Zinc oxide (ZnO) is an attractive metal oxide material in optoelectronics because of its visible light-emitting property caused by various deep-level defects. To exploit this property to its full potential in optoelectronic device applications, it is necessary to synthesize quantum-dot sized ZnO and to obtain p-type ZnO for achieving a p-n homojunction. In this study, for the first time, Sb-doped p-ZnO quantum dots (QDs) were successfully synthesized with a doping concentration of 0.5, 1, 2, and 5 at.% by a facile solution process at a low temperature of 30 °C. The obtained Sb-doped p-ZnO QDs exhibited strong and broad deep-level emission due to various deep-level defects. The p-type conductivity of the Sb-doped p-ZnO QDs was confirmed by applying QDs to a channel layer in TFTs. By using the obtained Sb-doped p-ZnO QDs as a p-type layer and growing n-ZnO nanorods (NRs) hydrothermally on top of the p-ZnO QD layer, ZnO-based homojunction white light-emitting diodes (WLEDs) were successfully fabricated. The fabricated WLEDs exhibited naked-eye observable white light emitting over the entire visible spectral region.