Max-Planck-Institute for Solid State Research, Heisenbergstrasse 1, 70569 Stuttgart, Germany.
Nano Lett. 2010 Feb 10;10(2):466-71. doi: 10.1021/nl903167f.
Phonon-carrier interactions can have significant impact on device performance. They can be probed by measuring the phonon lifetime, which reflects the interaction strength of a phonon with other quasi-particles, in particular charge carriers as well as its companion phonons. The carrier phonon and phonon-phonon contributions to the phonon lifetime can be disentangled from temperature-dependent studies. Here, we address the importance of phonon-carrier interactions in Joule-heated graphene constrictions in order to contribute to the understanding of energy dissipation in graphene-based electronic devices. We demonstrate that gapless graphene grants electron-phonon interactions uncommon significance in particular at low carrier density. In conventional semiconductors, the band gap usually prevents the decay of phonons through electron-hole generation and also in metals or other semimetals the Fermi temperature is excessively large to enter the regime where electron-phonon coupling plays such a dominant role as in graphene in the investigated phonon temperature regime from 300 to 1600 K.
声子-载流子相互作用会对器件性能产生重大影响。通过测量声子寿命可以探测到这种相互作用，声子寿命反映了声子与其他准粒子（特别是电荷载流子及其伴生声子）相互作用的强度。通过温度相关研究，可以将声子-载流子和声子-声子对声子寿命的贡献分离开来。在本研究中，我们关注了焦耳加热石墨烯限制中的声子-载流子相互作用的重要性，以有助于理解基于石墨烯的电子器件中的能量耗散。我们证明了无带隙的石墨烯赋予了电子-声子相互作用在特定低载流子密度下的不寻常重要性。在传统半导体中，带隙通常会阻止通过电子-空穴产生使声子衰减，而且在金属或其他半金属中，费米温度过高，无法进入电子-声子耦合在声子温度范围 300 到 1600 K 中扮演如此主导角色的区域，而在该声子温度范围内，电子-声子耦合在石墨烯中起着主导作用。
