High performance photodiode based on MoS2/pentacene heterojunction

Photodiodes based on monomolecular layer MoS2/pentacene heterojunction were fabricated and characterized. Similar to other organic photodetectors, the device performances are strongly dependent on the incident optical power. The unoptimized device with Al top electrode, exhibited a fairly high photo responsivity of 0.27 A/W, external quantum efficiency (EQE) of 51.3% and specific detectivity (D∗) of 4.81 × 1011 Jones for red light of 655 nm wavelength. These performances exceed not only the Schottky photodiode based on pentacene, and mono or few layer MoS2 based photodiodes, but also the most organic photodiodes reported recently. More importantly, with Au as the top electrode, the device performances could be further improved, the photoresponsivity, EQE and D∗ reached 0.31 A/W, 58.1%, and 1.55 × 1013 Jones, respectively at the same voltage biasing.