Two-dimensional SnSe2/Bi2Se3 Vertically Stacked Heterostructures for Enhanced Photoresponse through Tuning Layer Coverage

Two-dimensional materials have attracted much attention due to their unique structures and excellent optoelectronic properties. In this work, we fabricated c-axis-aligned SnSe 2 /Bi 2 Se 3 2D heterostructures via a hydrothermal technique, where the epitaxial growth of Bi 2 Se 3 nanoplates is achieved on SnSe 2 microplate substrates. The electronic states at the interfaces can be regulated facilely via tuning the Bi 2 Se 3 nanoplate coverage. The heterostructure not only increases the wavelength range over which light is absorbed, but also promotes the separation and migration of photo-excited charge carriers. Therefore, the heterostructure-based photodetector attains a photoresponse that outperforms those devices composed of pure SnSe 2 and Bi 2 Se 3 by a factor of 3.0 and 4.9, respectively. Furthermore, the optimal heterostructure generates a photocurrent of 289 μA cm -2 under ultraviolet illumination, which surpasses those of recently reported state-of-the-art photodetectors. Accordingly, this work establishes an effective approach for developing low-cost, high-perfomance optoelectronic devices based on 2D chalcogenides.