The Deposition of High-Quality HfO2 on Graphene and the Effect of Remote Oxide Phonon Scattering

TL;DR

This study demonstrates high-quality HfO2 deposition on graphene, revealing how remote oxide phonon scattering from both substrate and over-layer impacts carrier mobility, which is crucial for optimizing graphene-based electronic devices.

Contribution

It reports the successful atomic layer deposition of high-quality HfO2 on graphene and quantifies the influence of remote oxide phonon scattering on device performance.

Findings

Carrier mobility reaches 20,000 cm²/Vs at low temperature.

Surface phonon modes at 54 meV limit room temperature mobility.

HfO2 quality and phonon effects are critical for graphene device optimization.

Abstract

We demonstrate the atomic layer deposition of high-quality HfO2 film on graphene and report the magnitude of remote oxide phonon (ROP) scattering in dual-oxide graphene transistors. Top gates with 30 nm HfO2 oxide layer exhibit excellent doping capacity of greater than 1.5x10^(13)/cm^(2). The carrier mobility in HfO2-covered graphene reaches 20,000 cm^(2)/Vs at low temperature, which is the highest among oxide-covered graphene and compares to that of pristine samples. The temperature-dependent resistivity exhibits the effect of ROP scattering from both the SiO2 substrate and the HfO2 over-layer. At room temperature, surface phonon modes of the HfO2 film centered at 54 meV dominate and limit the carrier mobility to ~20,000 cm^(2)/Vs. Our results highlight the important choice of oxide in graphene devices.