▎ 摘　　要

We synthesize a series of CVD h-BN films and perform critical infrared spectroscopic characterization. For high-temperature (HT, Temp = 1400 degrees C) grown h-BN thin film, only E-1u-mode infrared phonon is activated demonstrating highly aligned 2D h-BN planes over large area, whereas low-temperature (LT, Temp = 1000 degrees C) grown film shows two phonon peaks, E-1u and A(2u), due to stacking of h-BN plane at tilted angle. For CVD graphene transferred on HT h-BN/SiO2/Si substrate, interband transition spectrum sigma(1) 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 sigma(1) defined by effective temperature is reduced from 400K for G/SiO2/Si to 300K 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. Published by AIP Publishing.