Boron nitride monolayer growth on vicinal Ni(1 1 1) surfaces systematically studied with a curved crystal

Abstract

The structural and electronic properties of hexagonal boron nitride (hBN) grown on stepped Ni surfaces are systematically investigated using a cylindrical Ni crystal as a tunable substrate. Our experiments reveal homogeneous hBN monolayer coating of the entire Ni curved surface, which in turn undergoes an overall faceting. The faceted system is defined by step-free hBN/Ni(111) terraces alternating with strongly tilted hBN/Ni(115) or hBN/Ni(110) nanostripes, depending on whether we have Atype or B-type vicinal surfaces, respectively. Such deep substrate self-organization is explained by both the rigidity of the hBN lattice and the lack of registry with Ni crystal planes in the vicinity of the (111) surface. The analysis of the electronic properties by photoemission and absorption spectroscopies reveal a weaker hBN/Ni interaction in (110)-and (115)-oriented facets, as well as an upward shift of the valence band with respect to the band position at the hBN/Ni(111) terrace.

Why a Good Catalyst Can Turn Out Detrimental to Good Polymerization

“…Since the cylinder axis is the [11̅0] direction, {100} (A-type) vicinals with close-packed steps are found on one side and {111} (B-type) vicinals on the other, up to α ± 15° (which corresponds to [21̅1̅] and [2̅11]­directions, respectively). The sample, which is described in more detail in the Supporting Information file (Figure S1) and ref , is easily prepared by standard sputtering–annealing cycles and its quality controlled with LEED, which shows the characteristic α-dependent spot splitting …”

“…43,44 For adsorbate-induced faceting, the adlayer/substrate interface registry acts as the driving force. 45 A closer view of the system at 350 K allows one to observe the composition of the layer covering the (335) patches, which in turn explains the preference for a local (335) orientation. A graphic sketch is superimposed to the STM topographic image in the 350 K inset, while lower panels contain the sideview drawings of the transition.…”

“…In order to investigate the role of the surface steps in the Ullmann coupling reaction, we investigate the self-assembly and subsequent polymerization of DBTP into PPP wires on a Au crystal surface curved around the (111) plane. Curved substrates offer the possibility to rationally assess chemical reactions in stepped surfaces by allowing to tune the step density on the same sample. ,− , Using X-ray photoemission spectroscopy (XPS), STM, angle-resolved photoemission spectroscopy (ARPES), and low energy electron diffraction (LEED), we map the DBTP-covered Au curved surface at different temperatures. Detailed analysis of such surface scans reveals the early and abrupt debromination and polymerization near individual steps at all vicinal angles, as compared to the smoother process observed at flat (111) terraces.…”

Atomically‐Precise Texturing of Hexagonal Boron Nitride Nanostripes

“…[21] For hBN/metal systems, characteristic facets are expected for step periodicities that match an entire number of hBN cells. [22] In the hBN/Rh system, we may compare the step spacing in the Rh(337) plane with the distance www.advancedsciencenews.com www.advancedscience.com between contiguous N rows in hBN. As shown in Figure 3c, the (337) plane can be viewed as an alternating sequence of (112) and (113) terraces, resulting in a l 337 = 1.1 nm lattice constant perpendicular to the steps.…”

“…Uniaxial vicinal planes with different terrace orientations, such as (110), (110), or (201), as well as other metals, such as Pt, Pd, Ru, or Cu should be explored. [ 5 ] hBN‐induced faceting appears to be the rule rather than the exception, [ 22 ] and this can serve to pinpoint new “magic,” well‐matched surfaces, such as Rh(337), and to find nanostriped patterns with varied textures.…”