Environment-insensitive and gate-controllable photocurrent enabled by bandgap engineering of MoS2junctions.
Two-dimensional (2D) materials are composed of atomically thin crystals with an enormous surface-to-volume ratio, and their physical properties can be easily subjected to the change of the chemical environment. Encapsulation with other layered materials, such as hexagonal boron nitride, is a common practice; however, this approach often requires inextricable fabrication processes. Alternatively, it is intriguing to explore methods to control transport properties in the circumstance of no encapsulated layer. This is very challenging because of the ubiquitous presence of adsorbents, which can lead to charged-impurity scattering sites, charge traps, and recombination centers. Here, we show that the short-circuit photocurrent originated from the built-in electric field at the MoS2junction is surprisingly insensitive to the gaseous environment over the range from a vacuum of 1 × 10-6Torr to ambient condition. The environmental insensitivity of the short-circuit photocurrent is attributed to the characteristic of the diffusion current that is associated with the gradient of carrier density. Conversely, the photocurrent with bias exhibits typical persistent photoconductivity and greatly depends on the gaseous environment. The observation of environment-insensitive short-circuit photocurrent demonstrates an alternative method to design device structure for 2D-material-based optoelectronic applications.
Department of Physics, National Taiwan University, Taipei 106, Taiwan.|Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan.
Fu-Yu
FY
Shih
Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan.
Yueh-Chun
YC
Wu
Department of Physics, National Taiwan University, Taipei 106, Taiwan.
Yi-Siang
YS
Shih
Department of Physics, National Sun Yat-sen University, Kaohsiung, Taiwan.
Ming-Chiuan
MC
Shih
Department of Physics, National Taiwan University, Taipei 106, Taiwan.|Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan.
Tsuei-Shin
TS
Wu
Department of Materials Science and Engineering, National Taiwan University, Taipei 106, Taiwan.
Po-Hsun
PH
Ho
Department of Materials Science and Engineering, National Taiwan University, Taipei 106, Taiwan.
Chun-Wei
CW
Chen
Department of Physics, National Taiwan University, Taipei 106, Taiwan.
Yang-Fang
YF
Chen
Department of Physics, National Taiwan University, Taipei 106, Taiwan.|Institute of Physics, Academia Sinica, Taipei 115, Taiwan.
Ya-Ping
YP
Chiu
Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan.
Wei-Hua
WH
Wang