Plasmon-Enhanced Photovoltaic Characteristics of Black Phosphorus-MoS₂ Heterojunction

Van der Waals p-n heterojunctions, consist of atomically thin two-dimensional (2D) layer semiconductors, have opened a promising avenue for the realization of ultrathin and ultralight photovoltaic solar cells. This feature enables them particularly be suitable as the micro/nanoscale solar energy-conversion units integrated in wireless power supply micro/nano-systems. However, solar energy harvest in these heterojunctions is hindered by inherent weak interlayer interaction at such ultrathin thickness. Herein, a novel integrated strategy by embedding metallic plasmonic pentamers optical nano-antenna array (ONAA) onto overlap region of black phosphorus-molybdenum disulfide (BP-MoS₂) p-n heterojunction is firstly exploited under both a near-infrared laser (λ = 830 nm) and standardized AM1.5G solar irradiation. Results show that profiting from plasmon-induced "hot" electrons and thermal field generating from gigantic near-field enhancement in 15 nm-ultrashort nanogap ONAAs and high intrinsic build-in field in atomically overlap region, this integrated configuration displays enhanced photovoltaic properties. Maximum short-circuits current (I_sc = 0.53 μA) and open circuit voltage (V_oc = 0.2 V) had been attained. Additional fill factor of 14% and double power conversion efficiencies amplification are measured via comparison of device without/with ONAAs. These findings strongly demonstrate this reliable enhancement strategy with integration of plasmonic physics into 2D heterojunctions for realizing energy harvesting unit in the wireless power supply micro/nano-systems.