Electronic Properties of Boron Phosphide Semiconductors

Boron phosphide (BP) is a III–V compound semiconductor that crystallises predominantly in the zinc-blende and wurtzite structures in bulk form, and can be stabilised as a hexagonal monolayer in two-dimensional form. In its cubic phase BP exhibits a direct band gap of approximately 2.0 eV at room temperature, high thermal conductivity and excellent mechanical hardness. Charge carriers in bulk BP display high mobilities, and intrinsic p-type conductivity is often observed due to native defects. Two-dimensional BP expands the application spectrum by offering a moderate band gap (0.9–1.4 eV), ultrahigh carrier mobility and strong optical absorption across ultraviolet, visible and near-infrared wavelengths. The electronic properties of BP can be tuned by strain engineering, surface functionalisation, defect incorporation and heterostructure formation. These abilities underpin its promise for optoelectronic devices, thermoelectric energy conversion, solar-energy harvesting and photocatalysis. Recent advances in synthesis methods, first-principles modelling and device integration highlight the global significance of BP as a versatile semiconductor platform.

Research from Nature Portfolio

Electro-optical Properties of Strained Monolayer Boron Phosphide Recent theoretical work has employed tight-binding methods combined with linear response theory to map how tensile and compressive biaxial strain alter the electronic band structure and optical conductivity of a monolayer of hexagonal BP. Tensile strain was shown to widen the direct band gap up to 1.45 eV, while compressive strain reduced it to around 1.14 eV. The pristine monolayer exhibits isotropic optical absorption peaks near 4 eV; biaxial strain preserves this isotropy whereas uniaxial strain induces anisotropic optical behaviour and shifts the main absorption features. This study underscores strain as a precise tool for tailoring BP’s absorption edge and optoelectronic response.

Thermoelectric Transports in Pristine and Functionalised Boron Phosphide Monolayers First-principles calculations combined with Boltzmann transport theory have revealed that a free-standing BP monolayer, with a moderate band gap of 0.90 eV and ultrahigh carrier mobility, attains a room-temperature thermoelectric figure of merit (ZT) of 0.255. Surface functionalisation with hydrogen or fluorine drastically lowers the lattice thermal conductivity, favouring thermoelectric conversion, but concurrently diminishes carrier mobility and limits net ZT gain. These results identify intrinsic BP as a promising two-dimensional thermoelectric and delineate the trade-offs imposed by chemical functionalisation.

Electronic Properties of Boron Phosphide Semiconductors publication trend

The graph below shows the total number of articles in electronic properties of boron phosphide semiconductors across all publications each year (not limited to Nature Index journals).

Technical terms

Band gap: Energy difference between the valence band maximum and conduction band minimum that determines a semiconductor’s optical absorption edge.

Carrier mobility: Measure of how quickly electrons or holes can move through a material under an applied electric field.

Type-II band alignment: Heterostructure configuration in which the valence band edge of one layer lies above that of its partner while the conduction band edge lies below, promoting spatial separation of electrons and holes.

Seebeck coefficient: Voltage developed per unit temperature difference across a material, indicating its thermoelectric behaviour.

Thermoelectric figure of merit (ZT): Dimensionless parameter (ZT = S²σT/κ) quantifying a material’s efficiency for converting heat to electricity, where S is Seebeck coefficient, σ is electrical conductivity and κ is thermal conductivity.

Biaxial strain: Uniform mechanical deformation applied in two orthogonal in-plane directions, used to tune electronic and optical properties.

Two-dimensional monolayer: Material consisting of a single atomic or molecular layer, offering enhanced quantum confinement and surface-sensitive properties.

P-type semiconductor: Semiconductor in which the majority charge carriers are holes, often arising from acceptor impurities or native defects.

References

1. First-principles investigation of a type-II BP/Sc 2 CF 2 van der Waals heterostructure for photovoltaic solar cells. Nanoscale Advances (2023).
2. Theoretical Calculation and Experimental Studies of Boron Phosphide Polycrystalline Synthesized at High Pressure and High Temperature. Nanomaterials (2025).
3. Electro-optical properties of strained monolayer boron phosphide. Scientific Reports (2023).
4. Thermoelectric transports in pristine and functionalized boron phosphide monolayers. Scientific Reports (2021).
5. Theoretical proposal of a revolutionary water-splitting photocatalyst: The monolayer of boron phosphide. Applied Surface Science (2022).