Optical control of multiple resistance levels in graphene for memristic applications

TL;DR

This paper demonstrates optically tunable multiple resistance states in graphene/hBN heterostructures, enabling memristor applications for neuromorphic computing through visible light modulation of doping levels.

Contribution

It introduces a novel optically controlled memristor using graphene/hBN heterostructures with multiple resistance levels, supported by a quantitative model.

Findings

Optical excitation of charge carriers modulates graphene doping levels.

Multiple resistance states achieved via light-induced doping.

Proposed memristive crossbar array for vector-matrix multiplication.

Abstract

Neuromorphic computing has emphasized the need for memristors with non-volatile, multiple conductance levels. This paper demonstrates the potential of hexagonal boron nitride (hBN)/graphene heterostructures to act as memristors with multiple resistance states that can be optically tuned using visible light. The number of resistance levels in graphene can be controlled by modulating doping levels, achieved by varying the electric field strength or adjusting the duration of optical illumination. Our measurements show that this photodoping of graphene results from the optical excitation of charge carriers from the nitrogen-vacancy levels of hBN to its conduction band, with these carriers then being transferred to graphene by the gate-induced electric field. We develop a quantitative model to describe our observations. Additionally, utilizing our device architecture, we propose a memristive crossbar array for vector-matrix multiplications.