Temperature-dependent Raman scattering provides valuable information on electron–phonon coupling and phonon anharmonicity of graphene. In this study, we show an enhancement of Joule heating in graphene by confining the current flow in a narrow channel. In addition, we performed a detailed analysis of the anharmonic effect in the hBN/monolayer graphene/hBN heterostructure based on the behaviour of the full-width at half maximum of the G mode with increasing electric power: a non-monotonic trend, leading to the key of approximation of the electronic temperature in graphene. We believe our results could offer a convenient analysis tool to study electron–phonon coupling and anharmonic phonon-decay processes in a high-temperature regime.

温度依赖性拉曼散射为石墨烯的电子-声子耦合和声子非谐性提供了有价值的信息。在这项研究中，我们通过限制狭窄通道中的电流显示出石墨烯中焦耳热的增强。此外，我们根据G模式的半峰全宽随功率增加的行为，对hBN /单层石墨烯/ hBN异质结构中的非谐效应进行了详细分析：非单调趋势，导致石墨烯中电子温度近似的关键。我们相信我们的结果可以提供一种方便的分析工具，以研究高温条件下的电子-声子耦合和非谐声子-衰变过程。