High performance complementary WS₂ devices with hybrid Gr/Ni contacts

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional (2D) transition metal dichalcogenides (TMDs) show promise for solid-state electronics.
• Challenges include Fermi level pinning and doping difficulties, hindering high-performance complementary devices.

Purpose of the Study:

• To develop a doping-free method for carrier type modulation in 2D materials.
• To investigate the performance of hybrid contacts for 2D material-based devices.

Main Methods:

• Fabrication of hybrid graphene/nickel (Gr/Ni) contacts on WS2.
• Asymmetric contact engineering with Ni and Gr/Ni on multilayer WS2.
• Characterization of device performance, including rectification and photovoltaic properties.

Main Results:

• Achieved n-type to p-type carrier switching in WS2 via hybrid Gr/Ni contacts.
• Demonstrated synergistic p-n diode characteristics with current rectification >10^4.
• Observed high photovoltaic performance with photoresponsivity of 4 × 10^4 A/W at 532 nm.

Conclusions:

• Hybrid Gr/Ni contacts effectively alleviate Fermi level pinning and enable carrier type modulation in WS2.
• The developed technique facilitates high-performance 2D material-based complementary electronics and optoelectronics.
• This doping-free approach offers a pathway for next-generation 2D electronic and optoelectronic devices.