Title: Intrinsic p-type W-based transition metal dichalcogenide by substitutional Ta-doping,
Abstract: Two-dimensional (2D) transition metal dichalcogenides (TMDs) have recently
emerged as promising candidates for future electronics and optoelectronics.
While most of TMDs are intrinsic n-type semiconductors due to electron donating
which originates from chalcogen vacancies, obtaining intrinsic high-quality
p-type semiconducting TMDs has been challenging. Here, we report an
experimental approach to obtain intrinsic p-type Tungsten (W)-based TMDs by
substitutional Ta-doping. The obtained few-layer Ta-doped WSe2 (Ta0.01W0.99Se2)
field-effect transistor (FET) devices exhibit competitive p-type performances,
including ~10^6 current on/off at room temperature. We also demonstrate high
quality van der Waals (vdW) p-n heterojunctions based on Ta0.01W0.99Se2/MoS2
structure, which exhibit nearly ideal diode characteristics (with an ideality
factor approaching 1 and a rectification ratio up to 10^5) and excellent
photodetecting performance. Our study suggests that substitutional Ta-doping
holds great promise to realize intrinsic p-type W-based TMDs for future
electronic and photonic applications.