Singh Anand Kumar, Singh Arun Kumar, Sinha Sita Ram Prasad
Department of Electronics and Communication Engineering, Institute of Engineering and Technology, Lucknow 226021, India.
Department of Pure and Applied Physics, Guru Ghasidas Vishwavidyalaya, Bilaspur 495009, Chhattisgarh, India.
ACS Omega. 2021 Dec 28;7(1):744-751. doi: 10.1021/acsomega.1c05394. eCollection 2022 Jan 11.
It is critical to modulate the Fermi level of graphene for the development of high-performance electronic and optoelectronic devices. Here, we have demonstrated the modulation of the Fermi level of chemical vapor deposition (CVD)-grown monolayer graphene (MLG) via doping with nanoparticles to macromolecules such as titanium dioxide nanoparticles (TiO NPs), nitric acid (HNO), octadecyltrimethoxysilane (OTS) self-assembled monolayer (SAM), and poly(3,4-ethylene-dioxythiophene):polystyrene sulfonate (PEDOT:PSS). The electronic properties of pristine and doped graphene samples were investigated by Raman spectroscopy and electrical transport measurements. The right shifting of G and 2D peaks and reduction in 2D to G peak intensity ratio ( / ) assured that the dopants induced a p-type doping effect. Upon doping, the shifting of the Dirac point towards positive voltage validates the increment of the hole concentration in graphene and thus downward shift of the Fermi level. More importantly, the combination of HNO/TiO NP doping on graphene yields a substantially larger change in the Fermi level of MLG. Our study may be useful for the development of graphene-based high-performance flexible electronic devices.
对于高性能电子和光电器件的发展而言，调节石墨烯的费米能级至关重要。在此，我们展示了通过用纳米颗粒至大分子如二氧化钛纳米颗粒（TiO NPs）、硝酸（HNO）、十八烷基三甲氧基硅烷（OTS）自组装单分子层（SAM）以及聚（3,4 - 乙撑二氧噻吩）：聚苯乙烯磺酸盐（PEDOT:PSS）进行掺杂，来调节化学气相沉积（CVD）生长的单层石墨烯（MLG）的费米能级。通过拉曼光谱和电输运测量研究了原始和掺杂石墨烯样品的电子性质。G峰和2D峰的右移以及2D与G峰强度比（/）的降低确保了掺杂剂诱导了p型掺杂效应。掺杂后，狄拉克点向正电压的移动证实了石墨烯中空穴浓度的增加，从而费米能级向下移动。更重要的是，石墨烯上HNO/TiO NP掺杂的组合在MLG的费米能级上产生了显著更大的变化。我们的研究可能对基于石墨烯的高性能柔性电子器件的发展有用。
