Enhanced Photoresponse of SnSe-Nanocrystals-Decorated WS2 Monolayer Phototransistor

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• 作者：Zhiyan Jia ; Jianyong Xiang ; Fusheng Wen ; Ruilong Yang ; Chunxue Hao ; Zhongyuan Liu
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：February 24, 2016
• 年：2016
• 卷：8
• 期：7
• 页码：4781-4788
• 全文大小：483K
• ISSN：1944-8252

文摘

Single-layer WS₂ has shown excellent photoresponse properties, but its promising applications in high-sensitivity photodetection suffer from the atomic-thickness-limited adsorption and band-gap-limited spectral selectivity. Here we have carried out investigations on WS₂ monolayer based phototransistors with and without decoration of SnSe nanocrystals (NCs) for comparison. Compared to the solely WS₂ monolayer, SnSe NCs decoration leads to not only huge enhancement of photoresponse in visible spectrum but also extension to near-infrared. Under excitation of visible light in a vacuum, the responsivity at zero gate bias can be enhanced by more than 45 times to ∼99 mA/W, and the response time is retained in millisecond level. Particularly, with extension of photoresponse to near-infrared (1064 nm), a responsivity of 6.6 mA/W can be still achieved. The excellent photoresponse from visible to near-infrared is considered to benefit from synergism of p-type SnSe NCs and n-type WS₂ monolayer, or in other words, the formed p-n heterojunctions between p-type SnSe NCs and n-type WS₂ monolayer.