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

A critical point drying (CPD) technique is reported with supercritical CO2 as a cleaning step for graphene field-effect transistors (GFETs) microfabricated on oxidized Si wafers, which results in an increase of the field-effect mobility and a decrease of the impurity doping. It is shown that the polymeric residues remaining on graphene after the transfer process and device microfabrication are significantly reduced after the CPD treatment. Moreover, the CPD effectively removes ambient adsorbates such as water therewith reducing the undesirable p-type doping of the GFETs. It is proposed that CPD of electronic, optoelectronic, and photonic devices based on 2D materials as a promising technique to recover their intrinsic properties after the microfabrication in a cleanroom and after storage at ambient conditions.

Automated summary

A critical point drying (CPD) technique using supercritical CO2 as a cleaning step for graphene field-effect transistors (GFETs) on oxidized Si wafers is reported, which improves the field-effect mobility and reduces impurity doping. The CPD treatment significantly reduces polymeric residues on graphene and effectively removes ambient adsorbates, such as water, thus reducing undesirable p-type doping of GFETs. It is proposed that CPD is a promising technique to restore the intrinsic properties of 2D materials-based electronic, optoelectronic, and photonic devices after microfabrication and storage at ambient conditions.