Ultraviolet Electroluminescence from ZnS@ZnO Core–Shell Nanowires/p-GaN Introduced by Exciton Localization

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• 作者：Xuan Fang ; Zhipeng Wei ; Yahui Yang ; Rui Chen ; Yongfeng Li ; Jilong Tang ; Dan Fang ; Huimin Jia ; Dengkui Wang ; Jie Fan ; Xiaohui Ma ; Bin Yao ; Xiaohua Wang
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：January 27, 2016
• 年：2016
• 卷：8
• 期：3
• 页码：1661-1666
• 全文大小：451K
• ISSN：1944-8252

文摘

We investigate the electroluminescence (EL) from light emitting diodes (LEDs) of ZnO nanowires/p-GaN structure and ZnS@ZnO core–shell nanowires/p-GaN structure. With the increase of forward bias, the emission peak of ZnO nanowires/p-GaN structure heterojunction shows a blue-shift, while the ZnS@ZnO core–shell nanowires/p-GaN structure demonstrates a changing EL emission; the ultraviolet (UV) emission at 378 nm can be observed. This discrepancy is related to the localized states introduced by ZnS particles, which results in a different carrier recombination process near the interfaces of the heterojunction. The localized states capture the carriers in ZnO nanowires and convert them to localized excitons under high forward bias. A strong UV emission due to localized excitons can be observed. Our results indicated that utilizing localized excitons should be a new route toward ZnO-based ultraviolet LEDs with high efficiency.