Electron tunneling through atomically flat and ultrathin hexagonal boron nitride (h-BN) on gold-coated mica was investigated using conductive atomic force microscopy. Low-bias direct tunneling was observed in mono-, bi-, and tri-layer h-BN. For all thicknesses, Fowler-Nordheim tunneling (FNT) occurred at high bias, showing an increase of breakdown voltage with thickness. Based on the FNT model, the barrier height for tunneling (3.07 eV) and dielectric strength (7.94 MV/cm) of h-BN are obtained; these values are comparable to those of SiO 2.
Bibliographical noteFunding Information:
This work was supported by the NSF under Grant No. DMR-1122594, FENA FCRP, Air Force MURI, and DARPA under the CERA program.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)