Infrared study of large scale h-BN film and graphene/h-BN heterostructure

Kwangnam Yu, Jiho Kim, Chul Lee, A. Rang Jang, Hyeon Suk Shin, Keun Soo Kim, Young Jun Yu, E. J. Choi

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

We synthesize a series of CVD h-BN films and perform critical infrared spectroscopic characterization. For high-temperature (HT, Temp = 1400 °C) grown h-BN thin film, only E1u-mode infrared phonon is activated demonstrating highly aligned 2D h-BN planes over large area, whereas low-temperature (LT, Temp = 1000 °C) grown film shows two phonon peaks, E1u and A2u, due to stacking of h-BN plane at tilted angle. For CVD graphene transferred on HT h-BN/SiO2/Si substrate, interband transition spectrum σ1 shifts strongly to lower energy compared with that on LT h-BN/SiO2/Si and on bare SiO2/Si substrates, revealing that the residual carrier density n in graphene is suppressed by the use of HT h-BN layer. Also, the interband transition width of σ1 defined by effective temperature is reduced from 400 K for G/SiO2/Si to 300 K for HT h-BN/SiO2/Si. The behaviors of n and effective temperature show that the HT h-BN film can decouple CVD graphene from the impurity and defect of SiO2 leading to a large scale free-standing like graphene.

Original languageEnglish
Article number241910
JournalApplied Physics Letters
Volume108
Issue number24
DOIs
StatePublished - 13 Jun 2016

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