Tunable self-assembly of one-dimensional nanostructures with orthogonal directions

Abstract

High-temperature exposure of a Mo(110) surface to borazine (HBNH) 3 leads to the formation of two distinctly different self-assembling nanostructures. Depending on the substrate temperature during preparation, either well-aligned, ultra-thin boron nanowires or a single-layer stripe structure of hexagonal boron nitride forms. Both structures show one-dimensional (1D) characteristics, but in directions perpendicular to each other. It is also possible to grow the two phases in coexistence. The relative weights are controlled by the sample temperature during preparation.Keywords Hexagonal boron nitride (h-BN) Á Boron Á One-dimensional nanostructures Á Nanowire Á Photoemission Á Scanning tunneling microscopy (STM) Á Low energy electron diffraction (LEED)In nanoscience and nanotechnology, there is an ubiquitous need for arranging nanometer-sized objects on surfaces in an orderly way. The atomic lattices of stable inorganic materials are usually too narrowly spaced for such applications, and research has focused on surfacesuperstructures with periodicities in the one to a few nanometer range, which can serve as templates e.g., for the formation of ordered layers of well-separated molecules, or for the growth of ordered metallic deposits and monodisperse metallic clusters [1]. Onedimensional (1D) superstructures represent an important class of templates, with confining potentials for electrons, molecules or metallic adsorbates along one direction parallel to the surface. Examples for 1D superstructures on surfaces include vicinal surfaces [2,3] submonolayer oxygen adsorbate structures on Cu(110) [4] or submonolayer structures of larger molecules organized into stripes by long-range, substrate-mediated interaction [5]. However, these 1D templates are often not very stable and not well ordered on a micrometer scale.Monolayer structures of hexagonal boron nitride (h-BN) on transition metal surfaces have received much interest recently. On Ni(111), which has a lattice spacing that is nearly equal to that of h-BN (2.49 Å for nickel, 2.50 Å for h-BN), the chemical vapor deposition (CVD) of benzene-like borazine (HBNH) 3 at 1050 K leads to very uniform epitaxial monolayers [6]. On Rh(111) the large lattice mismatch causes the h-BN to form a highly ordered mesh-like nanostructure with a periodicity of about 3 nm: the nanomesh [7]. On Pd(110) and Pd(111), where the lattice mismatch is even larger, continuous single-layer films are observed that exhibit a variety of moiré patterns [8,9]. A common aspect of these boron nitride layers is that, as a result of the high preparation temperatures, they represent chemically inert and highly temperatureresistant nanotemplates for the production of ordered molecular films or monodisperse metal clusters. It would thus be desirable to have also 1D templates based on this material.In this letter, we report two new self-assembling nanostructures grown by high-temperature CVD of borazine on the (110) surface of bcc molybdenum. This surface has a centered rectangular structure that is n...

Nanostructured and architectured boron nitride from boron, nitrogen and hydrogen-containing molecular and polymeric precursors

“…The question arose, of whether rhodium was the only substrate where mesh formation was possible or if it also appeared on other substrates, maybe with different values for properties such as the mesh cell size. The growth of BN was therefore investigated for a large variety of transition metal surfaces such as Pd [81,82], Ni(1 1 0) [83] and (1 1 1) [84,85], Ru(0 0 0 1) [86], Pt(1 1 1) [87], Mo(1 1 0) [88] and Cr(1 1 0) [89]. It should be mentioned that Paffett et al were the first to report the decomposition of BZ on Pt(1 1 1) and Ru(0 0 1 1) surfaces below 1000 8C [90].…”

Hexagonal boron nitride on transition metal surfaces

“…Originally, the preparation of a single layer of h-BN was achieved on the Rh(111) surface [1,2], but recently similar structures have been grown on Ru(0001) [3][4][5], Pt(111) [4,6,7], Ni(111) [8][9][10], Cu(111) [10], Pd(111) [11], and Ag(111) [12]. One-dimensional structures of h-BN have been produced using the same procedure on Cr(110) [13], Fe(110) [14], and Mo(110) [15]. Using similar recipes, graphene structures on most of these TM surfaces have also been obtained [5,16].…”

Epitaxial growth of hexagonal boron nitride on Ag(111)

“…5 So far, the epitaxial growth of boronitrene layers has been investigated for many transition-metal ͑TM͒ surfaces and, depending on substrate symmetry and lattice misfits, a large variety of superstructures has been observed. [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] In this Brief Report, the epitaxial growth of boronitrene layers on Ag͑111͒ is investigated in order to extend the list of experimental studies to the late TM. According to a recent ab initio density-functional study 23 the bonding between boronitrene layers and TM surfaces is largest for the elements in the 4d row but it decreases with an increasing number of d electrons.…”