Improved light emission from n-ZnO/p-Si heterojunction with HfO₂ as an electron blocking layer

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• 作者：Zhao Chen^a ; Borui Li^a ; Xiaoming Mo^b ; Kai Zhou^a ; Songzhan Li^c ; Zengcai Song^a ; Hongwei Lei^a ; Jian Wen^a ; Ziqiang Zhu^a ; Guojia Fang^a ; ^{gjfang@whu.edu.cn}
• 关键词：ZnO ; Heterojunction ; Light emission ; Carrier transport mechanism ; Crystallite HfO2
• 刊名：Journal of Luminescence
• 出版年：2017
• 出版时间：April 2017
• 年：2017
• 卷：184
• 期：Complete
• 页码：211-216
• 全文大小：1356 K
• 卷排序：184

文摘

Light-emitting diodes (LEDs) based on ZnO were fabricated on a p-Si substrate by using a pulsed laser deposition system. Significant electroluminescence (EL) improvement was demonstrated with the insertion of an HfO2 electron blocking layer (EBL) in n-ZnO/p-Si heterojunctions. Distinct near-band-edge emission at around 392 nm accompanying by a broadly strong visible emission was achieved when a proper thickness of HfO2 EBL was used. Current-voltage and capacitance-voltage measurements confirmed that a proper thickness of the HfO2 EBL can effectively balance the injection of electrons and holes, resulting in an increase of radiative recombination in the ZnO active layer and thus enhancing the EL performance of the devices. Five independent emissions corresponding to five different transition processes were proposed to clarify the EL origination of the n-ZnO/HfO2/p-Si heterojunction LEDs by Gaussian deconvolutions. It is hoped that results in this work should be helpful for the development of ZnO-based LEDs that can integrate ZnO with the Si planar technology.