# Highly Efficient Conductivity Modulation via Stacked Multi-Gate Graphene Ambipolar Transistors

## TL;DR

This paper introduces a stacked multi-gate graphene transistor that efficiently modulates conductivity while preserving ambipolar behavior, offering a promising design for high-performance graphene electronics.

## Contribution

The novel stacked multi-gate design enables synergistic conductivity modulation with low carrier concentration and preserved ambipolar symmetry.

## Key findings

- A three-layer stacked graphene structure shows pronounced ambipolar transfer characteristics.
- The device exhibits improved transconductance compared to conventional single-layer graphene transistors.
- Simulations reveal the impact of mobility, doping, and stacking layers on conductivity modulation.

## Abstract

The exceptional adjustability and ambipolar behavior of graphene offer significant potential for next-generation optoelectronics, where the conductivity of graphene is primarily modulated by the interface field of heterojunction. However, interface defects, which are inevitably introduced during fabrication, severely limit the effectiveness of gate voltage modulation. Although the layer-by-layer transfer method can effectively enhance conductivity, it also raises the carrier concentration and impairs the symmetry of ambipolar characteristics. This work presents a stacked multi-gate graphene transistor in which synergistic modulation enables efficient regulation of channel conductivity while maintaining low carrier concentration. Simulations are carried out to analyze how mobility, doping concentration, and the number of stacking layers influence the modulation of conductivity. Experimentally, a three-layer stacked graphene structure with distributed source and drain electrodes is fabricated. The device exhibits pronounced ambipolar transfer characteristics and demonstrates a clear improvement in transconductance compared to its conventional one-layer graphene counterpart. This research offers a feasible design strategy for high-performance, vertically integrated graphene-based electronic devices.