Modified MXene: promising electrode materials for constructing Ohmic contacts with MoS₂ for electronic device...

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Developing efficient molybdenum disulfide (MoS2)-based electronic devices requires suitable electrode materials for Ohmic contacts.
• MXene materials are emerging as potential candidates for electrodes in advanced electronic applications.

Purpose of the Study:

• To investigate pristine and modified MXene (Ta2C, Ta2CF2, Ta2C(OH)2) monolayers as electrode materials for MoS2.
• To evaluate the contact properties and transport characteristics of MoS2-based field-effect transistors (FETs) using these MXene electrodes.

Main Methods:

• Density functional theory (DFT) calculations.
• Non-equilibrium Green's function (NEGF) simulations.
• Transport property simulations of two-probe field-effect transistors (FETs).

Main Results:

• Chemical bonding and strong orbital hybridization were observed at the MoS2/Ta2C interface.
• Ohmic contacts were achieved with MoS2/Ta2C, MoS2/Ta2CF2, and MoS2/Ta2C(OH)2 interfaces.
• Ta2CF2 and Ta2C(OH)2 electrodes formed Ohmic contacts, while Ta2C formed an n-type Schottky barrier.
• FETs with MoS2/Ta2C(OH)2 electrodes exhibited half the resistance of those with MoS2/Ta2CF2 electrodes.

Conclusions:

• Ta2CF2 and Ta2C(OH)2 MXene monolayers are promising electrode materials for achieving Ohmic contacts with MoS2 in FETs.
• The use of small-molecule fragments as buffer layers can effectively facilitate Ohmic contacts between metal electrodes and semiconductors.