Promoting Photosensitivity and Detectivity of the Bi/Si Heterojunction Photodetector by Inserting a WS2 Layer

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• 作者：Jiandong Yao ; Zhaoqiang Zheng ; Jianmei Shao ; Guowei Yang
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：December 9, 2015
• 年：2015
• 卷：7
• 期：48
• 页码：26701-26708
• 全文大小：476K
• ISSN：1944-8252

文摘

Layered transition metal dichalcogenides (TMDs) have been proven to be essential building blocks for the high-performance optoelectronic devices as a result of their favorable bandgaps, extraordinary light absorption, and closed surface electronic structures. However, the in-depth exploration of their operating mechanism as insertion layers in heterojunction photodetectors is scarce. Here, we demonstrate that a Bi/Si heterojunction photodetector can achieve a superior performance by inserting a WS₂ layer. A high photosensitivity of 1.4 脳 10⁸ cm²/W and an outstanding detectivity of 1.36 脳 10¹³ cm Hz^1/2 W^鈥? are obtained, which are comparable or even surpass those of state-of-art commercial photodetectors. The working mechanism of the Bi/WS₂/Si sandwich-structured photodetector is unveiled, including the efficient passivation of the interface, enhancement of light absorption, and selective carrier blocking. Finally, a good voltage tunability of the photoresponse is also demonstrated. These findings are significant to the deep understanding on the integration of layered TMDs with conventional semiconductors, and they provide an attractive methodology to develop layered TMDs in a multi-junction system.