Strain Driven Electrical Bandgap Tuning of Atomically Thin WSe<sub>2</sub>
Md Akibul Islam, Eric Nicholson, Nima Barri, Momoko Onodera, Danny Starkov, Peter Serles, Shuo He, Boran Kumral, Ali Zavabeti, Haleh Shahsa, Teng Cui, Guorui Wang, Tomoki Machida, Chandra Veer Singh, Tobin Filleter
Abstract
Abstract Tuning electrical properties of 2D materials through mechanical strain has predominantly focused on n‐type 2D materials like MoS 2 and WS 2 , while p‐type 2D materials such as WSe 2 remain relatively unexplored. Here, the impact of controlled mechanical strain on the electron transport characteristics of both mono and bi‐layer WSe 2 is studied. Through coupling atomic force microscopy (AFM) nanoindentation techniques and conductive AFM, the ability to finely tune the electronic band structure of WSe 2 is demonstrated. The research offers valuable mechanistic insights into understanding how WSe 2 's electronic properties respond to mechanical strain, a critical prerequisite for the development of flexible photoelectronic devices. It is also observed that under high pressure, the AFM tip/monolayer WSe 2 /metal substrate junction transitions from Schottky to Ohmic contact, attributed to significant charge injection from the substrate to the WSe 2 . These findings are significant for designing efficient metal/semiconductor contact in thin and flexible PMOS (p‐type Metal–Oxide–Semiconductor) devices.