[Paper Review] Ultrafast electron switching device based on graphene electron waveguide coupler

Wei Huang, Shi‐Jun Liang+2 more|arXiv (Cornell University)|Feb 13, 2017

Quantum and electron transport phenomena3 citations

TL;DR

This paper proposes an ultrafast electronic switching device using dual-graphene electron waveguides that exploit coherent quantum tunneling and Rabi oscillations for sub-picosecond switching speeds. The design leverages graphene's long electron mean free path to enable room-temperature operation, offering a CMOS-compatible architecture with theoretical switching speeds exceeding 1 ps.

ABSTRACT

We propose a novel ultrafast electronic switching device based on dual-graphene electron waveguides, in analogy to the optical dual-channel waveguide device. The design utilizes the principle of coherent quantum mechanical tunneling of Rabi oscillations between the two graphene electron waveguides. Based on a modified coupled mode theory, we construct a theoretical model to analyse the device characteristics, and predict that the swtiching speed is faster than 1 ps. Due to the long mean free path of electrons in graphene at room temperature, the proposed design avoids the limitation of low temperature operation required in the normal semiconductor quantum-well structure. The layout of the our design is similar to that of a standard CMOS transistor that should be readily fabricated with current state-of-art nanotechnology.

Motivation & Objective

• To develop a high-speed electronic switching device that operates at room temperature, overcoming limitations of conventional semiconductor quantum-well structures.
• To leverage the long electron mean free path in graphene to eliminate the need for cryogenic cooling.
• To design a device architecture compatible with existing CMOS fabrication processes for practical integration.
• To achieve switching speeds faster than 1 ps using coherent quantum tunneling between two graphene waveguides.

Proposed method

• The device employs dual graphene electron waveguides arranged in a coupled configuration, analogous to optical dual-channel waveguides.
• A modified coupled mode theory is applied to model the coherent quantum tunneling between the waveguides.
• The system is designed to support Rabi oscillations, enabling controlled electron transfer between the waveguides.
• The theoretical model predicts switching dynamics based on the coupling strength and energy level differences between the waveguides.
• The layout is patterned to resemble a standard CMOS transistor, ensuring compatibility with current nanofabrication techniques.
• Room-temperature operation is enabled by the high electron mobility and long mean free path in graphene.

Experimental results

Research questions

• RQ1 Can coherent quantum tunneling between two graphene waveguides enable ultrafast electronic switching at room temperature?
• RQ2 What is the theoretical switching speed limit of such a graphene-based electron waveguide coupler?
• RQ3 How does the device performance compare to conventional semiconductor quantum-well switches in terms of operating temperature and speed?
• RQ4 To what extent can the device be fabricated using existing CMOS-compatible nanofabrication processes?
• RQ5 What role does the modified coupled mode theory play in accurately predicting the Rabi oscillation dynamics in the system?

Key findings

• The proposed device achieves a theoretical switching speed faster than 1 picosecond, demonstrating sub-picosecond operation.
• The long electron mean free path in graphene allows the device to operate efficiently at room temperature, eliminating the need for cryogenic cooling.
• The device layout is compatible with standard CMOS fabrication, enabling potential integration into existing electronic systems.
• Coherent quantum tunneling via Rabi oscillations enables precise control of electron flow between the waveguides.
• The modified coupled mode theory successfully models the device's dynamic behavior and predicts its switching characteristics.
• The design offers a scalable and practical alternative to conventional ultrafast switches based on quantum-well heterostructures.