Li Xiangyang, Ruan Shuangchen, Zhu Haiou
College of Applied Technology, Shenzhen University, Shenzhen 518060, China.
College of New Energy and New Materials, Shenzhen Technology University, Shenzhen 518118, China.
Nanomaterials (Basel). 2022 Aug 13;12(16):2777. doi: 10.3390/nano12162777.
High responsivity has been recently achieved in a graphene-based hybrid photogating mechanism photodetector using two-dimensional (2D) semiconductor nanosheets or quantum dots (QDs) sensitizers. However, there is a major challenge of obtaining photodetectors of fast photoresponse time and broad spectral photoresponse at room temperature due to the high trap density generated at the interface of nanostructure/graphene or the large band gap of QDs. The van der Waals interfacial coupling in small bandgap 2D/graphene heterostructures has enabled broadband photodetection. However, most of the photocarriers in the hybrid structure originate from the photoconductive effect, and it is still a challenge to achieve fast photodetection. Here, we directly grow SnS nanoflakes on graphene by the physical vapor deposition (PVD) method, which can avoid contamination between SnS absorbing layer and graphene and also ensures the high quality and low trap density of SnS. The results demonstrate the extended broad-spectrum photoresponse of the photodetector over a wide spectral range from 375 nm to 1550 nm. The broadband photodetecting mechanisms based on a photogating effect induced by the transferring of photo-induced carrier and photo-hot carrier are discussed in detail. More interestingly, the device also exhibits a large photoresponsivity of 41.3 AW and a fast response time of around 19 ms at 1550 nm. This study reveals strategies for broadband response and sensitive photodetectors with SnS nanoflakes/graphene.
最近，在一种基于石墨烯的混合光闸机制光电探测器中，使用二维（2D）半导体纳米片或量子点（QD）敏化剂实现了高响应度。然而，由于在纳米结构/石墨烯界面处产生的高陷阱密度或量子点的大带隙，在室温下获得具有快速光响应时间和宽光谱光响应的光电探测器存在重大挑战。小带隙二维/石墨烯异质结构中的范德华界面耦合实现了宽带光检测。然而，混合结构中的大多数光载流子源自光电导效应，实现快速光检测仍然是一个挑战。在这里，我们通过物理气相沉积（PVD）方法在石墨烯上直接生长SnS纳米片，这可以避免SnS吸收层与石墨烯之间的污染，还能确保SnS的高质量和低陷阱密度。结果表明，该光电探测器在375nm至1550nm的宽光谱范围内具有扩展的广谱光响应。详细讨论了基于光生载流子和光热载流子转移引起的光闸效应的宽带光检测机制。更有趣的是，该器件在1550nm处还表现出41.3AW的大光响应度和约19ms的快速响应时间。这项研究揭示了制备具有SnS纳米片/石墨烯的宽带响应和灵敏光电探测器的策略。
