Controllable p-Type Doping Strategy for High-Performance 2D Material Complementary Inverters.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Semiconductor Device Engineering

Background:

• Achieving controllable p-type doping in 2D semiconductors like tungsten diselenide (WSe2) is critical for modulating electrical properties in semiconductor devices.
• Current doping strategies often struggle with precise control, particularly for p-type modulation in WSe2.

Purpose of the Study:

• To present a novel, controllable doping strategy for WSe2 transistors using surface oxidation.
• To demonstrate the modulation of carrier density and threshold voltage through controlled oxidation.
• To evaluate the performance of doped WSe2 transistors in complementary metal-oxide-semiconductor (CMOS) devices.

Main Methods:

• Surface oxidation of WSe2 transistors at 200 °C in air for controlled durations.
• Characterization of carrier density and mobility modulation in WSe2 channels.
• Fabrication and testing of CMOS inverters using doped p-type WSe2 transistors.

Main Results:

• Precise modulation of hole density in WSe2 from 1 x 10^11 cm^-2 to 3.5 x 10^12 cm^-2 was achieved by varying oxidation time.
• High carrier mobility (94.3 cm^2·V^-1·s^-1) was maintained during the doping process.
• Doped p-type WSe2 transistors in a CMOS inverter exhibited a high gain (52) and low static power (0.256 nW) at 1 V bias.

Conclusions:

• Surface oxidation offers a reliable method for controllable p-type doping of WSe2 transistors.
• This technique enables balanced carrier transport for n-type and p-type transistors in CMOS circuits.
• The findings support the fabrication of high-performance and reliable 2D electronic circuits.