CVD-Grown Monolayer Graphene-Based Geometric Diode for THz Rectennas

Area of Science:

• Terahertz (THz) technology
• Graphene-based electronics
• Semiconductor device physics

Background:

• Metal-insulator-metal (MIM) diodes face limitations in resistance, capacitance, and cut-off frequency for THz rectennas.
• Existing THz geometric diodes based on monolayer graphene are not suitable for mass production due to reliance on exfoliated graphene.

Purpose of the Study:

• To demonstrate mass-producible terahertz geometric diodes using chemical vapor deposition (CVD)-grown monolayer graphene.
• To investigate the effect of varying neck widths on diode performance.

Main Methods:

• Fabrication of graphene geometric diodes with neck widths ranging from 250 nm to 50 nm.
• Experimental characterization of diode parameters including asymmetry, nonlinearity, zero-bias resistance, and responsivity.
• Verification of experimental results using particle-in-cell Monte Carlo simulations.

Main Results:

• Decreasing neck width enhanced diode parameters: asymmetry, nonlinearity, zero-bias resistance, and responsivity.
• The smallest reported neck width of 50 nm yielded an asymmetry ratio of 1.40 (at -2V to 2V) and zero-bias responsivity of 0.0628 A/W.
• Simulated current-voltage characteristics closely matched experimental findings.

Conclusions:

• CVD-grown monolayer graphene geometric diodes are a viable, mass-producible alternative for THz rectenna applications.
• Device performance scales favorably with reduced neck width, highlighting a pathway for optimization.
• The study validates the potential of these diodes for future THz technologies.