Growth of aligned and twisted hexagonal boron nitride on Ir(110)

Abstract

The growth of monolayer hexagonal boron nitride (h-BN) on Ir(110) through low-pressure chemical vapor deposition is investigated using low energy electron diffraction and scanning tunneling microscopy. We find that the growth of aligned h-BN on Ir(110) requires a growth temperature of 1500 K, whereas lower growth temperatures result in coexistence of aligned h-BN with twisted h-BN. The presence of the h-BN overlayer suppresses the formation of the nano-faceted ridge pattern known from clean Ir(110). Instead, we observe the formation of a ( 1 × n ) reconstruction, with n such that the missing rows are in registry with the h-BN/Ir(110) moiré pattern. Our moiré analysis showcases a precise methodology for determining both the moiré periodicity and the h-BN lattice parameter on an fcc(110) surface. Aligned h-BN on Ir(110) is found to be slightly compressed compared to bulk h-BN, with a monolayer lattice parameter of a h − B N = ( 0.2489 ± 0.0006 ) nm. The lattice mismatch with the substrate along 1 1 ˉ 0 gives rise to a moiré periodicity of a m = 2.99 ± 0.08 nm.