Observation of the hot phonon bottleneck mitigation in supported graphene

Rustam Gatamov, Andrey Baydin, Halina Krzyzanowska, Norman Tolk

Published 2018-08-02Version 1

Understanding the ultrafast carrier dynamics of graphene on a substrate is a fundamental step in the development of graphene based opto-electronic devices. In this letter, we present ultrafast pump-probe measurements of the supported graphene on quartz for a range of pump fluences that enable us to observe both decreased and enhanced probe transmission regimes on a femtosecond timescale. At a critical pump fluence, we observe a 10-fold decrease in the relaxation time constant which is correlated to fluence dependent transition from a bi-exponential to a single exponential decay pattern of the measured differential transmission. This suggests a mitigation of the hot phonon bottleneck that compromises the performance of graphene based devices.