A MoSe₂/Si heterojunction photodetector is constructed by depositing MoSe₂ film with vertically standing layered structure on Si substrate. Graphene transparent electrode is utilized to further enhance the separation and transport of photogenerated carriers. The device shows excellent performance in terms of wide response spectrum of UV–visible–NIR, high detectivity of 7.13 × 10¹⁰ Jones, and ultrafast response speed of ≈270 ns, unveiling the great potential for the heterojunction for high-performance optoelectronic devices.

Graphene–Si Schottky junction solar cells are promising candidates for high-efficiency, low-cost photovoltaic applications. However, their performance enhancement is restricted by strong carrier recombination and relative low barrier height. Here, we demonstrated the successful construction of high-efficiency graphene–planar Si solar cells via modification of the Si surface with a molecule monolayer as well as tuning the interface band alignment with an organic electron blocking layer. Methylated Si showed the capability to effectively suppress the surface carrier recombination, leading to a remarkable improvement of device efficiency. The recombination was further reduced by inserting a thin P3HT organic layer; the unique band alignment could prevent electron transfer from n-Si to the graphene anode so as to minimize the current leakage. These methods, along with careful control of the graphene doping level and layer number, gave rise to a power conversion efficiency (PCE) as high as 10.56%. The scalability of the devices was further investigated by studying the device area dependent photovoltaic performance.