Enhanced photo-response in p-Si/MoS2 heterojunction-based solar cells

High quality ultrathin transition-metal dichalcogenide films and their Vander Waals heterostructures are very promising for fabrication of optoelectronic devices for their superior photovoltaic performance, extreme flexibility and long lifetime due to suitable band gap and excellent light absorption capability. Designing the appropriate and suitable band structures of these materials is crucial for its promising applications. Especially, thin molybdenum disulfide (MoS2) film is further attractive as compare to its monolayer counterpart for broad-spectral photo-detectors and photovoltaic application. However, very little understanding regarding the underlying physics behind the photo-response behavior of thin MoS2 films is known. Here, we demonstrate a large photovoltaic response in thin MoS2 films which produces an enormous photo-generated carrier and enhance the photocurrent by forming a heterojunction with p-type Si substrate. MoS2 based photovoltaic devices efficiently produce high short-circuit photocurrent values of 18 mA/cm2 and reasonably high power-conversion efficiency up to 4.5%. The present work will provide valuable scientific input of layered MoS2 films for other emerging optoelectronic applications.