Phosphorene Heterostructure Nanodevices for Ultrafast Energy Harvesting and Next Generation Electronics

Abstract: Transition metal dichalcogenides (TMDCs) have recently shown much promise as thin layer semiconductors in application to transistor technology. TMDCs provide a unique vantage point for studying the properties of phosphorene, a highly efficient and tunable super-material. Phosphorene-TMDC heterostructure nanodevices have remained largely unexplored due to the lack of air stability observed in phosphorene under ambient conditions. This study investigates a novel nanofabrication technique that effectively enhances the air stability and practical scalability of graphene-analogous phosphorene. A phosphorene-WS2 heterostructure was first designed and synthesized via micromechanical exfoliation and dry transfer methods. A novel umbrella contact was fabricated using electron beam lithography which extended the electrical anode over the phosphorene heterojunction region. SEM, Raman spectroscopy, gate transport, and photocurrent response techniques were employed to characterize the device physically and electronically. Devices fabricated with an extended anodic contact remained functional for extended periods of time, suggesting that the contact had prevented the phosphorene from degradation in ambient conditions. Preliminary results obtained via current response indicate a promising heterojunction with high speed transistor properties. This work suggests the unprecedented longevity and practical scalability of phosphorene utilizing a novel contact nanofabrication technique. Potential applications of the nanodevice include next generation electronic devices, photodetectors, energy storage devices, and photovoltaic cells.