Enhanced n-doping of epitaxial graphene on SiC by bismuth

• Published in: Applied physics letters Vol. 113; no. 1
• Main Authors: Hu, Tingwei, Fang, Qinglong, Zhang, Xiaohe, Liu, Xiangtai, Ma, Dayan, Wei, Ran, Xu, Kewei, Ma, Fei
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 02-07-2018
• Subjects: Applied physics; Bismuth; Doping; Electron transfer; First principles; Graphene; Morphology; Spectrum analysis; Thermal decomposition
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.5029541

Doping in epitaxial graphene (EG) is challenging because of the high-temperature process and the ultra-thin nature of graphene. In this work, a facile one-step method is demonstrated to generate doping in EG with bismuth (Bi) during thermal decomposition of SiC, in which Bi atom flux acts as the doping source. Raman spectroscopy and scanning tunneling microscopy/spectroscopy are employed to characterize the quality, morphology and electronic properties of Bi doped EG. Both the intercalated and incorporated Bi atoms can be considered as dopants. It was found that the Dirac point shifts away from the Fermi level as a result of electron transfer from Bi to EG, and thus enhances the n-doping behavior of EG significantly. First principles calculations were done to address the enhanced n-doping of EG by Bi. This in-situ doping procedure can be extended to other metals, showing great potential applications in tailoring the performance of EG and significance to electronics in the future.