Grain Boundary Structures and Electronic Propertiesof Hexagonal Boron Nitride on Cu(111).

Grain boundaries (GBs) of hexagonalboron nitride (h-BN) grown on Cu(111) were investigated by scanningtunneling microscopy/spectroscopy (STM/STS). The first experimentalevidence of the GBs composed of square-octagon pairs (4|8 GBs) wasgiven, together with those containing pentagon-heptagon pairs (5|7GBs). Two types of GBs were found to exhibit significantly differentelectronic properties, where the band gap of the 5|7 GB was dramaticallydecreased as compared with that of the 4|8 GB, consistent with ourobtained result from density functional theory (DFT) calculations.Moreover, the present work may provide a possibility of tuning theinert electronic property of h-BN via grain boundary engineering. [ABSTRACT FROM AUTHOR]