Suspension and Measurement of Graphene and Bi2Se3 Atomic Membranes

TL;DR

This paper introduces a versatile lithography method for suspending atomic membranes like graphene and Bi2Se3, enabling advanced studies of their electronic properties with high mobility and stable electrode contacts.

Contribution

The authors developed a multi-level lithographical technique applicable to various materials, successfully fabricating suspended graphene and Bi2Se3 membranes with high mobility and low contact resistance.

Findings

Suspended graphene devices with mobility of 5500 cm^2/Vs.

First fabrication and measurement of free-standing Bi2Se3 membranes.

Bi2Se3 membranes exhibit low contact resistance and high mobility.

Abstract

Coupling high quality, suspended atomic membranes to specialized electrodes enables investigation of many novel phenomena, such as spin or Cooper pair transport in these two dimensional systems. However, many electrode materials are not stable in acids that are used to dissolve underlying substrates. Here we present a versatile and powerful multi-level lithographical technique to suspend atomic membranes, which can be applied to the vast majority of substrate, membrane and electrode materials. Using this technique, we fabricated suspended graphene devices with Al electrodes and mobility of 5500 cm^2/Vs. We also demonstrate, for the first time, fabrication and measurement of a free-standing thin Bi2Se3 membrane, which has low contact resistance to electrodes and a mobility of >~500 cm^2/Vs.