Critical Point Drying of Graphene Field-Effect Transistors Improves Their Electric Transport Characteristics

Area of Science:

• Materials Science
• Nanotechnology
• Solid State Physics

Background:

• Graphene field-effect transistors (GFETs) are crucial for next-generation electronics.
• Microfabrication and ambient storage can introduce impurities and adsorbates, degrading GFET performance.
• Polymeric residues and water contamination are significant issues affecting GFETs.

Purpose of the Study:

• To investigate the efficacy of critical point drying (CPD) with supercritical CO2 as a cleaning method for microfabricated GFETs.
• To evaluate the impact of CPD on removing polymeric residues and ambient adsorbates from graphene.
• To assess the influence of CPD on the electrical properties, specifically field-effect mobility and doping levels, of GFETs.

Main Methods:

• Microfabrication of GFETs on oxidized Si wafers.
• Application of critical point drying (CPD) using supercritical CO2 as a post-fabrication cleaning step.
• Characterization of GFETs before and after CPD treatment to assess electrical properties and surface contamination.

Main Results:

• CPD significantly reduces polymeric residues on graphene surfaces.
• CPD effectively removes ambient adsorbates, such as water, mitigating p-type doping in GFETs.
• GFETs treated with CPD exhibit increased field-effect mobility and decreased impurity doping.

Conclusions:

• CPD with supercritical CO2 is a highly effective cleaning technique for microfabricated GFETs.
• This method can restore and enhance the intrinsic properties of 2D material-based devices.
• CPD presents a promising approach for improving the performance and reliability of electronic, optoelectronic, and photonic devices.