Direct Observation of Structural Phase Transformations during Phosphorene Formation on Cu(111).

Blue phosphorene, a two-dimensional, hexagonal-structured, semiconducting phosphorus, has gained attention as it is considered easier to synthesize on metal surfaces than its allotrope, black phosphorene. Recent studies report different structures of phosphorene, for example, on Cu(111), but the underlying mechanisms of their formation are not known. Here, using a combination of in situ ultrahigh vacuum low-energy electron microscopy and in vacuo scanning tunneling microscopy, we determine the time evolution of the surface structure and morphology during the deposition of phosphorus on single-crystalline Cu(111).

Growth of Highly Oriented (VNbMoTaW)S Layers.

Compositional tunability, an indispensable parameter for modifying the properties of materials, can open up new applications for van der Waals (vdW) layered materials such as transition-metal dichalcogenides (TMDCs). To date, multielement alloy TMDC layers are obtained via exfoliation from bulk polycrystalline powders. Here, we demonstrate direct deposition of high-entropy alloy disulfide, (VNbMoTaW)S, layers with controllable thicknesses on free-standing graphene membranes and on bare and hBN-covered AlO(0001) substrates via ultra-high-vacuum reactive dc magnetron sputtering of the VNbMoTaW target in Kr and HS gas mixtures.

Borazine Promoted Growth of Highly Oriented Thin Films.

We report on a phenomenon, where thin films sputter-deposited on single-crystalline AlO(0001) substrates exposed to borazine─a precursor commonly used for the synthesis of hexagonal boron nitride layers─are more highly oriented than those grown on bare AlO(0001) under the same conditions. We observed this phenomenon in face-centered cubic Pd, body-centered cubic Mo, and trigonal TaC thin films grown on AlO(0001). Interestingly, intermittent exposure to borazine during the growth of TaC thin films on TaC yields better crystallinity than direct deposition of monolithic TaC.

Self-Organized Growth of 111-Oriented (VNbTaMoW)N Nanorods on MgO(001).

Refractory high-entropy alloy nitride, (VNbTaMoW)N, layers are grown on single-crystalline MgO(001) via ultrahigh vacuum direct current magnetron sputtering of a VNbTaMoW target in Kr/N gas mixtures at 1073 K. X-ray diffraction, scanning and transmission electron microscopy, and energy dispersive X-ray spectroscopy characterizations revealed the formation of B1-structured, 111-textured (VNbTaMoW)N with lattice parameter = 0.4249 nm.

Ultra-high vacuum dc magnetron sputter-deposition of 0001-textured trigonal α-TaC/AlO(0001) thin films.

We report on the effects of substrate temperature (1073 K ≤ ≤ 1373 K) and deposition time (= 3 ~ 30 min.) on the crystallinity of TaC/AlO(0001) thin films grown via ultra-high vacuum direct current magnetron sputtering of TaC target in 20 mTorr (2.7 Pa) pure Ar atmospheres.