Yadav Premlata, Srivastava Pawan Kumar, Ghosh Subhasis
Electronic Materials and Device Laboratory, School of Physical Sciences, Jawaharlal Nehru University, New Delhi-110067, India.
Nanoscale. 2015 Nov 21;7(43):18015-9. doi: 10.1039/c5nr04800a.
Excitonic transitions in graphene monolayers embedded in different dielectric environments have been investigated using combined absorption and transmission spectroscopy techniques. To vary the dielectric environment, graphene monolayer has been exfoliated in liquid medium. It has been shown that exciton binding energy decreases with increase in the dielectric constant of exfoliating solvents due to the screening of electron-electron and electron-hole interactions in graphene. The typical line shape of the excitonic peak in the absorption spectra is explained by the Fano resonance between the excitonic state and band continuum. Further it has been shown that, there exists a scaling relationship between the dielectric constant of the liquid and the exciton binding energy.
利用吸收光谱和透射光谱相结合的技术，研究了嵌入不同介电环境中的单层石墨烯中的激子跃迁。为了改变介电环境，单层石墨烯已在液体介质中剥离。结果表明，由于石墨烯中电子-电子和电子-空穴相互作用的屏蔽，激子结合能随着剥离溶剂介电常数的增加而降低。吸收光谱中激子峰的典型线形由激子态与能带连续体之间的法诺共振解释。此外，研究还表明，液体的介电常数与激子结合能之间存在标度关系。
