Homogeneous in-plane WSe2 P-N junctions for advanced optoelectronic devices.
Nanoscale
; 15(10): 4940-4950, 2023 Mar 09.
Article
em En
| MEDLINE
| ID: mdl-36786036
ABSTRACT
Conventional doping schemes of silicon (Si) microelectronics are incompatible with atomically thick two-dimensional (2D) transition metal dichalcogenides (TMDCs), which makes it challenging to construct high-quality 2D homogeneous p-n junctions. Herein, we adopt a simple yet effective plasma-treated doping method to seamlessly construct a lateral 2D WSe2 p-n homojunction. WSe2 with ambipolar transport properties was exposed to O2 plasma to form WOx on the surface in a self-limiting process that induces hole doping in the underlying WSe2via electron transfer. Different electrical behaviors were observed between the as-exfoliated (ambipolar) region and the O2 plasma-treated (p-doped) region under electrostatic modulation of the back-gate bias (VBG), which produces a p-n in-plane homojunction. More importantly, a small contact resistance of 710 Ω µm with a p-doped region transistor mobility of â¼157 cm2 V-1 s-1 was achieved due to the transformation of Schottky contact into Ohmic contact after plasma treatment. This effectively avoids Fermi-level pinning and significantly improves the performance of photodetectors. The resultant WSe2 p-n junction device thus exhibits a high photoresponsivity of â¼7.1 × 104 mA W-1 and a superior external quantum efficiency of â¼228%. Also, the physical mechanism of charge transfer in the WSe2 p-n homojunction was analyzed. Our proposed strategy offers a powerful route to realize low contact resistance and high photoresponsivity in 2D TMDC-based optoelectronic devices, paving the way for next-generation atomic-thickness optoelectronics.
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01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Nanoscale
Ano de publicação:
2023
Tipo de documento:
Article