Degradation Studies of Air-Exposed Black Phosphorous and Black Arsenic Phosphorous

Abstract

This work investigates the effects of oxygen and humidity on black phosphorous (BP) and black arsenic phosphorous (AsxP1−x ) flakes using Raman spectroscopy and in situ electric transport measurements (four-probe resistance and thermoelectric power, TEP). The results show that the incorporation of arsenic into the lattice of BP renders it more stable, with the degradation times for BP, As0.2P0.8, and As0.4P0.6 being 4, 5, and 11 days, respectively. The P-P Raman peak intensities were determined to decrease with exposure to oxygen and moisture. The TEP measurements confirmed that both BP and AsxP1−x are p-type semiconductors with the TEP of As0.4P0.6 stabilizing more slowly than that of BP. In addition, the four-probe resistance of BP and AsxP1−x stabilized significantly faster when exposed to air after being degassed in a vacuum. This was attributed to the charge transfer between the oxygen redox potential of air and the Fermi energy (EF) of the semiconductors.

Production of Magnetic Arsenic–Phosphorus Alloy Nanoribbons with Small Band Gaps and High Hole Conductivities

“…The residual weak magnetism is presently unassigned, although metal impurities in the bAsP framework may contribute a small paramagnetic signal. 49 The behavior changes dramatically with intercalation to Li(AsP) 9 , where the material is much more strongly paramagnetic at low magnetic fields, at both 1.8 and 300 K (Figure 3b), with a significantly weaker diamagnetic component. The temperature-dependent magnetic susceptibility of the Li(AsP) 9 in a 50 mT field shows a sharp drop below 3.9 K which is not present in the initial bAsP (SI, Figure S14).…”

“…The lithium ratio was defined versus a weight-averaged AsP atom (M w = 50.75), and three stoichiometries were used to create a range of intercalation compounds: Li(AsP) 4.5 , Li(AsP) 9 , and Li(AsP) 18 . The pXRD of Li(AsP) 9 shows the lithium intercalates successfully, seen as a significant downshift of all peaks, with the (020) peak maximum center 2θ shifting to 16.26°, implying an interlayer increase to 5.50 Å (Figure 1b). The general peak pattern is retained indicating that the general AsP framework structure is maintained.…”

“…By partial substitution of phosphorus with arsenic precursors in typical bP syntheses, so-called black AsP (bAsP) is formed with the orthorhombic puckered honeycomb lattice structure of bP, but with a fraction ( x ) of the P atoms replaced by As atoms (Figure a) over a continuum of As:P ratios . The introduction of arsenic modifies the properties of bP, for example, by increasing anisotropic thermal conductivity and improving stability in air . Crystals of bAsP are most commonly synthesized by mineralizer-assisted (Sn/SnI 4 or Au/Pb/PbI 2 ) vapor transport from red phosphorus and gray arsenic , although mineralizer-free and other syntheses, such as molecular beam deposition, are in development.…”

“… 7 The introduction of arsenic modifies the properties of bP, for example, by increasing anisotropic thermal conductivity 8 and improving stability in air. 9 Crystals of bAsP are most commonly synthesized by mineralizer-assisted (Sn/SnI 4 or Au/Pb/PbI 2 ) vapor transport from red phosphorus and gray arsenic 1 , 10 although mineralizer-free 11 and other syntheses, such as molecular beam deposition, 12 are in development. The properties of bAsP depend on the elemental ratio and, in theory, the distribution of atoms within the structure, although current syntheses are all assumed to form stochastic As/P distributions.…”