Fabrication of Graphene p-n-p Junctions with Contactless Top Gates

TL;DR

This paper presents a novel fabrication method for graphene p-n-p junctions using contactless, suspended top gates that minimize damage and doping, resulting in high-quality devices confirmed by transport measurements.

Contribution

A new multi-level lithography process for creating graphene p-n-p junctions with contactless, suspended top gates that avoids damage and simplifies fabrication.

Findings

Successful fabrication of high-quality graphene p-n-p junctions

Device mobility improved through annealing

Transport data confirms junction quality at various magnetic fields

Abstract

We developed a multi-level lithography process to fabricate graphene p-n-p junctions with the novel geometry of contactless, suspended top gates. This fabrication procedure minimizes damage or doping to the single atomic layer, which is only exposed to conventional resists and developers. The process does not require special equipment for depositing gate dielectrics or releasing sacrificial layers, and is compatible with annealing procedures that improve device mobility. Using this technique, we fabricate graphene devices with suspended local top gates, where the creation of high quality graphene p-n-p junctions is confirmed by transport data at zero and high magnetic fields.