Quantum scattering time and its implications on scattering sources in graphene

作者：Xia Hong, Ke Zou, Jun Zhu · 发表于：Physical Review B · 年份：2009 · DOI：10.1103/physrevb.80.241415 · 被引用次数：136 · 研究领域：Graphene research and applications、Nanopore and Nanochannel Transport Studies、Quantum and electron transport phenomena

We determine the quantum scattering time ${\ensuremath{\tau}}_{q}$ in six graphene samples with mobility of $4\text{ }400<\ensuremath{\mu}<17\text{ }000\text{ }{\text{cm}}^{2}/\text{V}\text{ }\text{s}$ over a wide range of carrier density $(1.2<n<6\ifmmode\times\else\texttimes\fi{}{10}^{12}/{\text{cm}}^{2})$. ${\ensuremath{\tau}}_{q}$ derived from Shubnikov--de Haas oscillation ranges $\ensuremath{\sim}25--74\text{ }\text{fs}$, corresponding to a single-particle level broadening of 4.5--13 meV. The ratio of the transport to quantum scattering time ${\ensuremath{\tau}}_{t}/{\ensuremath{\tau}}_{q}$ spans 1.5--5.1 in these samples, which can be quantitatively understood combining scattering from short-ranged centers and charged impurities located within 2 nm of the graphene sheet. Our results suggest that charges residing on the ${\text{SiO}}_{2}$ surface play a dominant role in limiting carrier mobility in current samples.