School of Physical Sciences, Jawaharlal Nehru University , New Delhi 110067, India.
ACS Appl Mater Interfaces. 2017 Feb 15;9(6):5375-5381. doi: 10.1021/acsami.6b13211. Epub 2017 Jan 31.
We report controlled doping in graphene monolayers through charge-transfer interaction by trapping selected organic molecules between graphene and underneath substrates. Controllability has been demonstrated in terms of shifts in Raman peaks and Dirac points in graphene monolayers. Under field effect transistor geometry, a shift in the Dirac point to the negative (positive) gate voltage region gives an inherent signature of n- (p-)type doping as a consequence of charge-transfer interaction between organic molecules and graphene. The proximity of organic molecules near the graphene surface as a result of trapping is evidenced by Raman and infrared spectroscopies. Density functional theory calculations corroborate the experimental results and also indicate charge-transfer interaction between certain organic molecules and graphene sheets resulting p- (n-)type doping and reveals the donor and acceptor nature of molecules. Interaction between molecules and graphene has been discussed in terms of calculated Mulliken charge-transfer and binding energy as a function of optimized distance.
我们通过在石墨烯和基底之间捕获选定的有机分子，报告了通过电荷转移相互作用对石墨烯单层进行的受控掺杂。通过石墨烯单层中拉曼峰和狄拉克点的移动来证明其可控性。在场效应晶体管几何结构中，狄拉克点向负（正）栅极电压区域的移动给出了 n-（p-）型掺杂的固有特征，这是有机分子和石墨烯之间的电荷转移相互作用的结果。拉曼和红外光谱证明了由于捕获而在石墨烯表面附近存在有机分子。密度泛函理论计算证实了实验结果，并表明某些有机分子与石墨烯片之间的电荷转移相互作用导致 p-（n-）型掺杂，并揭示了分子的供体和受体性质。通过计算的 Mulliken 电荷转移和结合能作为优化距离的函数，讨论了分子和石墨烯之间的相互作用。
