Creating Reversible p-n Junction on Graphene through Ferritin Adsorption

Area of Science:

• Materials Science
• Nanotechnology
• Biophysics

Background:

• Graphene-based field-effect transistors (G-FETs) require stable p-n junctions for advanced applications.
• Controlling surface charge and properties of graphene is crucial for device performance.

Purpose of the Study:

• To present an alternative method for constructing stable p-n junctions on G-FETs.
• To investigate the charge modification of ferritin via electron beam irradiation for G-FET applications.
• To demonstrate water-gate operation of the fabricated p-n junction.

Main Methods:

• Physical adsorption of ferritin (spherical protein shell) onto graphene.
• Electron beam (EB)-irradiation of native ferritin to alter its surface charge.
• Fabrication and characterization of p-n junctions on G-FETs.
• Water-gate operation testing.

Main Results:

• Stable p-n junctions were successfully constructed on G-FETs using ferritin.
• EB-irradiation reversed the native negative charge of ferritin to positive.
• EB-irradiation removed adsorbed charged impurities on graphene, shifting the Dirac point to Vg = 0.
• The G-FET with the ferritin-based p-n junction operated effectively using a water-gate.

Conclusions:

• Ferritin's charge can be controllably modified by EB-irradiation, enabling G-FET p-n junction fabrication.
• This method offers a novel approach for stable p-n junction construction and graphene property tuning.
• The developed G-FET demonstrates potential for water-gated electronic devices.