Interface Engineering and Substitutional Doping in In₂Ge₂Te₆ for High-Performance 2D p-Type FETs and CMOS Devices.

Area of Science:

• Materials Science
• Semiconductor Physics
• Nanotechnology

Background:

• Metal-semiconductor interfaces are critical for 2D semiconductor device performance, impacting charge carrier injection efficiency.
• High-performance contacts for emerging 2D semiconductors, particularly p-type materials, face challenges like Fermi-level pinning and defect scattering, leading to increased contact resistance.
• These interface issues create parasitic barriers that limit the operational efficiency of p-type devices.

Purpose of the Study:

• To investigate the combined effects of interface contact and doping engineering on optimizing the performance of the low effective mass p-type semiconductor In2Ge2Te6.
• To systematically explore strategies for reducing Schottky barrier height and contact resistance in 2D p-type field-effect transistors (FETs).
• To demonstrate the application of these strategies in fabricating high-performance 2D complementary metal oxide semiconductor (CMOS) devices.

Main Methods:

• Systematic exploration of interface contact and doping engineering on In2Ge2Te6.
• Introduction of optimized electrodes and region-selective oxygen doping.
• Characterization of Schottky barrier height and contact resistance reduction.
• Fabrication and testing of an In2Ge2Te6/MoS2 CMOS device.

Main Results:

• Reduced Schottky barrier height from 63 to 36 meV.
• Decreased contact resistance from 1.3 to 0.6 kΩ·µm.
• Achieved a voltage gain of 140 in an In2Ge2Te6/MoS2 CMOS device with low static power consumption (2.9 nW at 1 V).

Conclusions:

• Optimized electrode work function and impurity band creation effectively reduce contact barriers in 2D p-type semiconductors.
• The developed strategy offers a straightforward approach to enhance the performance of 2D p-type FETs and CMOS devices.
• This work paves the way for improved electronic devices based on emerging 2D materials.