Department of Electronics and Nanoengineering, Aalto University, Espoo 02150, Finland.
Nanoscale. 2019 Feb 14;11(7):3240-3247. doi: 10.1039/c8nr09248f.
van der Waals (vdW) heterostructures formed by stacking different two-dimensional layered materials have been demonstrated as a promising platform for next-generation photonic and optoelectronic devices due to their tailorable band-engineering properties. Here, we report a high photoresponsivity and broadband photodetector based on a WSe2/SnSe2 heterostructure. By properly biasing the heterostructure, its band structure changes from near-broken band alignment to type-III band alignment which enables high photoresponsivity from visible to telecommunication wavelengths. The highest photoresponsivity and detectivity at 532 nm are ∼588 A W-1 and 4.4 × 1010 Jones and those at 1550 nm are ∼80 A W-1 and 1.4 × 1010 Jones, which are superior to those of the current state-of-the-art layered transition metal dichalcogenides based photodetectors under similar measurement conditions. Our work not only provides a new method for designing high-performance broadband photodetectors but also enables a deep understanding of the band engineering technology in the vdW heterostructures possible for other applications, such as modulators and lasers.
由堆叠不同二维层状材料形成的范德华（vdW）异质结构由于其可调节的能带工程特性，已被证明是下一代光子和光电设备的有前途的平台。在这里，我们报告了一种基于 WSe2/SnSe2 异质结构的高光电响应率和宽带光电探测器。通过适当偏置异质结，可以将其能带结构从近带隙对准转变为 III 型带隙对准，从而实现从可见光到远程通信波长的高光电响应率。在 532nm 处的最高光电响应率和探测率约为 588A W-1 和 4.4×1010Jones，在 1550nm 处的最高光电响应率和探测率约为 80A W-1 和 1.4×1010Jones，优于在类似测量条件下基于当前最先进的二维过渡金属二卤化物的光电探测器。我们的工作不仅为设计高性能宽带光电探测器提供了一种新方法，而且还为 vdW 异质结构中的能带工程技术在其他应用（如调制器和激光器）中的应用提供了深入的理解。
