Improved performance of graphene transistors by strain engineering.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanoelectronics

Background:

• Graphene's unique electronic properties make it a promising material for next-generation electronic devices.
• Strain engineering is a technique used to modify material properties, but its application in graphene-based transistors requires further investigation.
• Understanding the impact of uniaxial strain on graphene heterojunctions is crucial for optimizing device performance.

Purpose of the Study:

• To investigate the effects of uniaxial strain on the transport properties of strained graphene heterojunctions.
• To explore the potential of using strained graphene hetero-channels for high-performance graphene transistors.
• To analyze the impact of strain on the operational characteristics of graphene field-effect transistors (FETs).

Main Methods:

• Numerical simulations were employed to model the behavior of strained graphene heterojunctions.
• Analysis focused on strain-induced deformation of the graphene bandstructure.
• Performance metrics of graphene transistors, including ON/OFF current ratio, transconductance, and transition frequency, were evaluated.

Main Results:

• A finite conduction gap was observed to open in strain junctions due to strain-induced bandstructure deformation.
• Strained graphene hetero-channels significantly improved graphene field-effect transistor (FET) operation, achieving ON/OFF current ratios exceeding 10^5.
• Graphene normal FETs exhibited high transconductance and good current saturation, leading to high voltage gain and transition frequencies in the hundreds of GHz.
• Graphene tunneling FETs demonstrated subthreshold swings below 30 mV/dec, along with gate-controllable negative differential conductance and current rectification.

Conclusions:

• Uniaxial strain is an effective method for engineering graphene's electronic properties and enhancing transistor performance.
• Strained graphene heterojunctions offer a viable route to achieving high-performance graphene transistors with excellent ON/OFF ratios and operational speeds.
• The observed phenomena in both normal and tunneling FETs highlight the potential of strain engineering for advanced nanoelectronic applications.