We employed conventional and time-resolved Raman spectroscopy to study the effects of electron-phonon and phonon-phonon interactions on the linewidth of the G phonon in both unintentionally and intentionally doped polycrystalline chemical vapor deposited (CVD) graphene samples. We directly measured the G phonon lifetime, observing a ≈14% decrease with doping up to E_F = 270 meV. The anticipated reduction of G phonon linewidth due to a decrement in electron-phonon contribution deviates from first principles calculations. CVD samples exhibit a ≈30% decrease in the electron-phonon coupling constant, λ_Γ(E_F = 0), compared to exfoliated graphene samples. Additionally, phonon-defect scattering makes a significant contribution to the G band linewidth in CVD graphene samples, owing to their lower crystal quality compared to exfoliated graphene.

我们采用传统和时间分辨拉曼光谱来研究电子-声子和声子-声子相互作用对无意和有意掺杂的多晶化学气相沉积 (CVD) 石墨烯样品中 G 声子线宽的影响。我们直接测量了 G 声子寿命，观察到当掺杂量达到E _F  = 270 meV 时，G 声子寿命减少了约 14%。由于电子声子贡献的减少而预期的 G 声子线宽的减小偏离了第一原理计算。CVD 样品的电子-声子耦合常数 λ _Γ ( E _F = 0），与剥离石墨烯样品相比。此外，声子缺陷散射对 CVD 石墨烯样品中的 G 带线宽做出了重大贡献，因为与剥离石墨烯相比，它们的晶体质量较低。