nl0c00704_si_001.pdf (1.54 MB)
Growth Kinetics of Two-Dimensional Hexagonal Boron Nitride Layers on Pd(111)
journal contribution
posted on 2020-03-06, 15:39 authored by Pedro Arias, Abbas Ebnonnasir, Cristian V. Ciobanu, Suneel KodambakaUsing in
situ variable-temperature scanning tunneling
microscopy (300–673 K) during chemical vapor deposition of
two-dimensional hexagonal boron nitride (hBN) on Pd(111) from borazine
precursor at pressures up to 10–6 mbar, we identify
the mechanisms leading to carpetlike uphill or downhill growth across
the Pd steps. Deposition at a higher rate and lower temperature promotes
uphill growth via preferential attachment at the ascending and descending
step-edges, whereas a lower deposition rate and higher temperature
lead to downhill growth via nucleation and growth of islands on Pd
terraces. We attribute this unusual growth behavior to differences
in temperature-dependent rates of hBN deposition at the steps versus
on the Pd terraces. Our results illustrate how growth mechanisms can
be activated by a pair of parameters (substrate temperature and partial
pressure of borazine) and provide new insights into the mechanisms
underlying carpetlike growth of hBN and other layered materials.