Yang Li, Cohen Marvin L, Louie Steven G
Department of Physics, University of California at Berkeley, California 94720, USA.
Nano Lett. 2007 Oct;7(10):3112-5. doi: 10.1021/nl0716404. Epub 2007 Sep 8.
We present a first-principles calculation of the optical properties of armchair-edged graphene nanoribbons (AGNRs) with many-electron effects included. The reduced dimensionality of the AGNRs gives rise to an enhanced electron-hole binding energy for both bright and dark exciton states (0.8-1.4 eV for GNRs with width approximately 1.2 nm) and dramatically changes the optical spectra owing to a near complete transfer of oscillator strength to the exciton states from the continuum transitions. The characteristics of the excitons of the three distinct families of AGNRs are compared and discussed. The enhanced excitonic effects found here are expected to be of importance in optoelectronic applications of graphene-based nanostructures.
我们给出了包含多电子效应的扶手椅型边缘石墨烯纳米带（AGNRs）光学性质的第一性原理计算。AGNRs的低维特性导致亮激子态和暗激子态的电子 - 空穴结合能增强（宽度约为1.2 nm的GNRs的结合能为0.8 - 1.4 eV），并且由于振子强度几乎完全从连续跃迁转移到激子态，从而极大地改变了光谱。比较并讨论了三种不同类型AGNRs的激子特性。这里发现的增强激子效应预计在基于石墨烯的纳米结构的光电子应用中具有重要意义。
