Ultrafast Diffusion at the Onset of Growth: O/Ru(0001)

Abstract

Nanoscopic clustering in a 2D disordered phase is observed for oxygen on Ru(0001) at low coverages and high temperatures. We study the coexistence of quasi-static clusters (with a characteristic length of ∼ 9Å) and highly mobile atomic oxygen which diffuses between the energy-inequivalent, threefold hollow sites of the substrate. We determine a surprisingly low activation energy for diffusion of 385 ± 20 meV. The minimum of the O − O interadsorbate potential appears to be at lower separations than previously reported.

Evolution of ordered nanoporous phases during h-BN growth: controlling the route from gas-phase precursor to 2D material by in situ monitoring

“…57 While the specular reflection gives an estimate of adsorbate coverage on the clean surface, the angular distribution provides insight in the time evolution of periodic structures being formed on the surface. 31,36 In the present work, CVD growth was performed at a set crystal temperature while monitoring the surface using repeated one-dimensional angular diffraction scans, where we observe the emergence and disappearance of additional superstructures followed by the formation of h-BN.…”

“…In particular, previous h-BN studies using real space methods 24–27 concentrate on local order in completed h-BN structures, while reciprocal space studies 28–30 have provided information about long-range order. 31…”

“…In particular, previous h-BN studies using real space methods [24][25][26][27] concentrate on local order in completed h-BN structures, while reciprocal space studies [28][29][30] have provided information about long-range order. 31 In this paper we present a systematic analysis, at various temperatures beyond the ones reported for best growth conditions (1050 to 1100 K 24,26,29 ) and at various dosing rates. By following h-BN growth in situ using helium atom scattering (HAS) we demonstrate the existence of metastable structures during the formation of h-BN from borazine (B 3 N 3 H 6 ).…”