Atomic and electronic structure of exfoliated black phosphorus

Abstract

Electronic structure, chemical bonding features, and electron charge density of the double-cubane single crystal [ Sb 7 S 8 Br 2 ] ( AlCl 4 ) 3 Appl. Phys. Lett. 98, 201903 (2011); 10.1063/1.3583674Structural characterization and electron-energy-loss spectroscopic study of pulsed laser deposited Li Nb O 3 films on a -sapphire Black phosphorus, a layered two-dimensional crystal with tunable electronic properties and high hole mobility, is quickly emerging as a promising candidate for future electronic and photonic devices. Although theoretical studies using ab initio calculations have tried to predict its atomic and electronic structure, uncertainty in its fundamental properties due to a lack of clear experimental evidence continues to stymie our full understanding and application of this novel material. In this work, aberration-corrected scanning transmission electron microscopy and ab initio calculations are used to study the crystal structure of few-layer black phosphorus. Directly interpretable annular dark-field images provide a three-dimensional atomic-resolution view of this layered material in which its stacking order and all three lattice parameters can be unambiguously identified. In addition, electron energy-loss spectroscopy (EELS) is used to measure the conduction band density of states of black phosphorus, which agrees well with the results of density functional theory calculations performed for the experimentally determined crystal. Furthermore, experimental EELS measurements of interband transitions and surface plasmon excitations are also consistent with simulated results. Finally, the effects of oxidation on both the atomic and electronic structure of black phosphorus are analyzed to explain observed device degradation. The transformation of black phosphorus into amorphous PO 3 or H 3 PO 3 during oxidation may ultimately be responsible for the degradation of devices exposed to atmosphere over time.

Surface structure determination of black phosphorus using photoelectron diffraction

“…The pioneering studies focused on determining the bulk atomic structure, for example, by X-ray diffraction [5] and neutron powder diffraction [26]. Recent results using scanning transmission electron microscopy [27] were also obtained for the bulk, with good agreement with the experimental results of X-ray diffraction. For the BP surface, a combined study using scanning tunneling microscopy (STM) and density functional theory (DFT) calculations [28] show that the surface atoms occupy almost the same position of the atoms in the bulk, except for a small perpendicular relaxation of the P1 and P2 surface atoms (see Fig.…”

“…The value obtained for b 2 was 3.23Å, which is ∼ 5% greater than the expected bulk value (3.07Å). However, a more recent study using scanning transmission electron microscopy (STEM) [27] Nevertheless, we can analyze more carefully the contraction of the b 1 distance and the buckling. As already mentioned, within the phosphorene layer, each atom is covalently bonded to three neighbours, with two bonds connecting the nearest P atoms in the same plane (d 1 ), and the third bond conecting P atoms between the top and bottom of the phosphorene layer (d 2 ), see Fig.…”

“…Although a large number of studies with theoretical predictions for phosphorene have been published recently [16,18,21,22,29], the experimental results reported use in general bulk BP samples [15,24,28,30] or few layers obtained by exfoliation [7,27,31]. The efficient production of a phosphorene single layer with its atomic structure and orientation characterized is still a technological challenge [4].…”

Controlled Sculpture of Black Phosphorus Nanoribbons

“…4,28 Figure 1c includes a STEM simulation (top) and a schematic illustration (bottom) of this arrangement in bilayer BP (see also section S2). Note that, as reported before, the STEM measurements report an image corresponding to projected positions of atoms a few layers deep.…”

Revealing the Origins of 3D Anisotropic Thermal Conductivities of Black Phosphorus

“…[ 2 ] The structure of BP makes it the most thermodynamically stable phosphorus allotrope at ambient temperature and pressure. Both monolayer (also called phosphorene) and few-layer BP fl akes obtained from mechanical exfoliation [ 19,20 ] have proven to be anisotropic 2D semiconductors with high carrier mobility, [ 5,[19][20][21] possessing a direct band gap tunable from 0.3 to 1.0 eV. [ 22 ] This combination of properties makes BP a great candidate for use in the next generation nanoelectronic and nanophotonic devices, compared even favorably to other well-studied 2D materials such as graphene, hexagonal boron nitride, and molybdenum disulfi de.…”