Non-monotonic temperature dependent transport in graphene grown by Chemical Vapor Deposition

TL;DR

This study investigates the unusual non-monotonic temperature dependence of resistivity in CVD-grown graphene, revealing the interplay of thermal activation, screening, and phonon effects influenced by environmental factors.

Contribution

It introduces a model considering thermal activation in electron-hole puddles to explain the anomalous temperature-dependent transport in CVD graphene.

Findings

Resistivity shows strong insulating behavior at low temperatures and metallic at high temperatures.

Carrier density modulation significantly affects the temperature dependence.

Transport properties are heavily influenced by environmental conditions.

Abstract

Temperature-dependent resistivity of graphene grown by chemical vapor deposition (CVD) is investigated. We observe in low mobility CVD graphene device a strong insulating behavior at low temperatures and a metallic behavior at high temperatures manifesting a non-monotonic in the temperature dependent resistivity.This feature is strongly affected by carrier density modulation. To understand this anomalous temperature dependence, we introduce thermal activation of charge carriers in electron-hole puddles induced by randomly distributed charged impurities. Observed temperature evolution of resistivity is then understood from the competition among thermal activation of charge carriers, temperature-dependent screening and phonon scattering effects. Our results imply that the transport property of transferred CVD-grown graphene is strongly influenced by the details of the environment