SnSe2/TiO2 heterostructures for broadband photodetection

Abstract

The formation of heterojunctions presents a novel architecture for photodetector applications, offering an expanded active surface area that enhances light absorption and overall performance. Recently, metal-dichalcogenides have attracted significant interest for future optoelectronic devices due to their exceptional electronic and optical properties. However, their application has been limited to narrow detection ranges. To overcome this, broadband photodetection can be achieved through the combination of two distinct materials in a heterostructure. Among these, SnSe₂ has gained significant attention as a promising material for next-generation optoelectronics. In this work, a vertical heterostructure formed by integrating SnSe₂ with hydrothermally grown TiO₂ nanorods. The TiO₂ nanorods, which were uniformly distributed across the surface, were synthesized using a hydrothermal method, while the SnSe₂ layer was deposited via thermal evaporation. This configuration increases the junction area of the heterostructure, enhancing its performance across a broad spectral range (400–800 nm). Upon 325 nm incidence, the SnSe₂/TiO₂ heterostructure demonstrates a remarkable high responsivity of 34.63 mA/W and a detectivity of 10⁷ Jones. This significantly enhanced optoelectronic performance of the SnSe₂/TiO₂ heterostructure offers great potential for the development of efficient broadband photodetectors.