Structural Characterization of Atomically Thin Hexagonal Boron Nitride via Raman Spectroscopy

A non-destruction evaluation of atomically thin hexagonal boron nitride h-BN films is critical to the U.S. Air Force and Department of Defense initiatives pursuing graphene-based electronic field effect transistors FETs capable of operating at terahertz frequencies. H-BN thin films an increase to the characteristic E2g 1367cm-1 h-BN peak intensity has been correlated to an increase in film thickness. Raman spectroscopy on a h-BN film with thicknesses of 7, 14, and 21 atoms 2.5nm, 5nm, 7.5nm respectively revealed a linear relationship between peak intensity and thickness. This relationship can mathematically be described as y0.0265x0.8084, and fits the data with a R2 value of 0.9986. There was no observed correlation between film thickness and full width at half maximum FWHM and there was no measured shift to the E2g peak with increasing film thickness.