Phosphorene (black phosphorus)

Also called black phosphorus, BP, few-layer black phosphorus, black arsenic, b-AsP

van der Waals crystal semiconductor

A semiconductor whose band gap changes strongly with the number of layers, filling the infrared range between graphene (no gap) and most TMDCs (large gap). It conducts differently along its two in-plane directions, which suits polarisation-sensitive light detectors. Its great weakness: it degrades in air within hours.

Cell: Rectangular, a = 3.31 Å (zigzag), b = 4.38 Å (armchair)
Atoms per cell: 4
P–P bonds: 2.22 and 2.24 Å
Height: 2.13 Å between the outer atom centres

Each phosphorus atom bonds to three others: two in its own plane and one in the plane 2.13 Å above or below. That puckers the layer into zigzag chains along a with an armchair profile along b, and the difference between the two directions shows up in the effective masses, the mobility and the optical absorption. One layer of bulk black phosphorus at room temperature (orthorhombic): a = 3.31 Å, b = 4.38 Å.

Data sheet

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Kind of sheet: van der Waals crystal
Peels off a layered crystal, one sheet at a time
Behaves as: semiconductor
Band gap: Direct at all thicknesses: ~0.3 eV in bulk rising to ~2 eV for the monolayer quasiparticle gap; monolayer optical gap ~1.3 eV because excitons are strongly bound

In colour: this family, 0.3–2 eV. In grey: the other 39 families on the catalogue’s chart, each at the middle of its range.
Thickness: ~0.53 nm (interlayer spacing)
Structure: Puckered orthorhombic layers with distinct armchair and zigzag directions; each phosphorus atom bonds to three neighbours
Space group: P (black phosphorus): bulk Cmce, monolayer Pmna
Bulk: the Materials Project crystal linked below. Monolayer: the 2DMatPedia layer, as a periodic slab
Stability: Degrades under ambient conditions within hours: light, oxygen and water together oxidise it to phosphorus oxides and acids, visible as droplets on the surface. Encapsulation in hBN or Al₂O₃ extends device lifetimes to months.
First made: 2014 – few-layer transistors by Li and colleagues (Fudan University and USTC) and by Liu and colleagues (Purdue); bulk black phosphorus first made by Bridgman in 1914
Materials Project: P (black phosphorus)
Computed crystal structure and properties
2DMatPedia: P
Computed monolayer, exfoliated from a bulk crystal of the same compound

Compare with other materials

What it looks like

A sealed glass ampoule holding a few dark grey, metallic-looking crystals, with a label that begins “Black Phos” and reads 0.18 grams. — Black phosphorus, the layered crystal that phosphorene is peeled from, sealed in a glass ampoule that keeps air and moisture out. Image: Alshaer666, CC BY-SA 3.0; resized.

Key properties

Layer-dependent direct gap from ~0.3 eV (bulk) to ~2 eV (monolayer, quasiparticle)
Hole mobility up to ~1,000 cm²/(V·s) at room temperature in ~10 nm flakes
Strong in-plane anisotropy: effective mass, mobility, optical absorption and thermal conductivity all differ between armchair and zigzag
Monolayer exciton binding energy of several hundred meV, strongly dependent on the dielectric environment

How it is made

Mechanical exfoliation of bulk crystals, ideally inside a glovebox
Bulk crystals by high-pressure conversion of red phosphorus, or by low-pressure mineraliser-assisted transport with Sn and SnI₄
Liquid-phase exfoliation in deoxygenated solvents – few-layer dispersions
Direct thin-film growth by pulsed laser deposition or CVD – early stage and poorly crystalline

Uses, and how close they are

Mid-infrared and polarisation-sensitive photodetectorsprototype
Anodes for lithium- and sodium-ion batteries (as composites)lab
Field-effect transistorslab

Readiness runs lab → prototype → pilot → deployed.

Open problems

Can scalable, air-stable passivation be achieved without degrading mobility?
Can crystalline black phosphorus films be grown directly at wafer scale?
How do the anisotropic excitons evolve with layer number and dielectric environment?

Going deeper

Short notes for specialists. Choose a lens in the header and yours comes first.

For theoreticians · your lens

Interlayer coupling is unusually strong for a van der Waals material and drives the gap from ~2 eV to ~0.3 eV. PBE underestimates badly, and the choice of dispersion correction changes interlayer distances and therefore gaps, so use HSE or GW with converged k-grids. Excitons are large and anisotropic, and modest strain strongly modulates the gap.

For experimentalists · your lens

Handle and exfoliate in a glovebox and encapsulate before exposing to light in air. Determine crystal orientation with polarisation-resolved Raman: the A¹g, B₂g and A²g modes near 362, 439 and 467 cm⁻¹ have angle-dependent intensities.

For engineers · your lens

Excellent infrared optoelectronic performance, but air instability and the lack of wafer-scale growth confine it to niche detectors at best; any product would need hermetic encapsulation.

In the research tracks

Theory frontiers

Growth methods

Recent news

The newest items tagged Phosphorene, from the news feed updated 5 Oct 2026.

Journal 1 Oct 2026 Nano Letters

Interfacing Two Topological Insulators, α -Bismuthene and β -Silicene, with a Rare-Earth Magnetic Monolayer

The integration of diverse electronic phenomena, such as magnetism and nontrivial topology, into a single low-dimensional system gives rise to unusual quantum effects. Here we combine two 2D topological insulators, α-bismuthene and β-silicene, with a Ho monolayer. Bismuthene is synthesized within a rarely realized…

TheoryExperimentAntimonene, bismuthene Phosphorene Silicene

Journal 30 Sep 2026 ACS Nano

Growth and Infrared Light Emission of Emerging van der Waals Semiconductors: Black Phosphorus and Tellurium

Infrared luminescent semiconductor materials and devices are fundamental to optoelectronic information technology. van der Waals (vdW) semiconductors, notably black phosphorus (BP) and tellurium (Te), possess a narrow direct bandgap and a low surface/Auger recombination rate, making them promising for infrared…

ExperimentPhosphorene

Preprintnot yet peer reviewed 29 Sep 2026 arXiv

Screening of Coulomb Interactions in MoS2 Nanoribbons: Enhanced Coulomb interactions, Antiscreening, and Edge Magnetism

MoS2 has attracted significant attention for its promising applications in optoelectronics, owing to the remarkable stability of its excitons and trions. These quasiparticles have large binding energies that arise from the MoS2 moderate band gap and the unconventional screening of Coulomb interactions in low…

TheoryPhosphorene Graphene MoS₂

Journal 25 Sep 2026 Advanced Optical Materials

Thin Phophorus‐Oxide‐Assisted Electrically Pumped Mid‐Infrared Light Emission in a Twisted Black Phosphorus Structure with Polarization Switching

Advanced Optical Materials, Volume 14, Issue 36, 25 September 2026.