Van der Waals broken-gap p-n heterojunction tunnel diode based on black phosphorus and rhenium disulfide

摘要： The broken-gap type-III van der Waals (vdW) heterojunction is of particular interest as there is no overlap between the energy bands of its two stacked materials. Despite several studies on straddling-gap (type-I) and staggered-gap (type-II) vdW heterojunctions, a comprehensive understanding of the current-transport and optoelectronic effects in a type-III broken-gap heterojunction remains elusive. Here, we report gate-tunable current rectifying characteristics in a black phosphorus (BP)/rhenium disulfide (ReS2) broken-gap p-n heterojunction diode. Current-transport in this heterojunction was modeled by using the Simmons approximation through direct tunneling and Fowler?Nordheim tunneling in low- and higher-bias regimes, respectively. We showed that a p-n diode based on a type-III heterojunction is mainly governed by tunneling-mediated transport, but that transport in a type-I p-n heterojunction is dominated by majority carrier diffusion in the higher-bias regime. Upon illumination with a 532-nm-wavelength laser, the BP/ReS2 broken-gap p-n heterojunction showed a photo responsivity of 8 mA/W at a laser power as high as 100 μW and photovoltaic energy conversion with an external peak quantum efficiency of 0.3%. Finally, we demonstrated a binary inverter consisting of BP p-channel and ReS2 n-channel thin film transistors for logic applications.