Black Phosphorus Field-Effect Transistor Technologies

Black phosphorus (BP) has emerged as a leading contender among two-dimensional semiconductors for field-effect transistor (FET) applications, owing to its direct, thickness-tunable bandgap and high intrinsic carrier mobility. The puckered lattice of BP yields pronounced in-plane anisotropy, enabling directional control of charge transport. Key advances have addressed fundamental challenges such as environmental stability, contact resistance and polarity control. Encapsulation strategies have preserved material quality under ambient conditions, while interface and contact engineering have mitigated Schottky barriers and enhanced on-state conductance. Tailored gate dielectrics and thermal treatments have further reduced subthreshold swing and improved electrostatic control. Together, these innovations pave the way for BP-based electronics in high-performance logic, flexible devices and broadband photodetectors, illustrating the global significance of BP FETs for next-generation nanoelectronic systems.

Research from Nature Portfolio

Encapsulating atomically thin BP within inert hexagonal boron nitride layers has realised ultra-clean interfaces, yielding room-temperature field-effect mobilities exceeding 1,300 cm² V⁻¹ s⁻¹ and on/off current ratios above 10⁵. At cryogenic temperatures, mobility further rises and clear quantum oscillations demonstrate two-dimensional hole gas behaviour, underscoring the potential for low-noise, high-sensitivity applications.

Control over transistor polarity and performance has been achieved via contact-metal choice and flake thickness. Aluminium contacts promote unipolar n-type switching in thinner flakes while yielding ambipolar behaviour in thicker layers, with balanced electron and hole mobilities approaching 950 cm² V⁻¹ s⁻¹ at room temperature. This work establishes a scalable route to complementary BP circuits without chemical doping.

A simple analytic Schottky barrier MOSFET model has been developed to describe BP FET transfer characteristics across a wide range of thicknesses. By quantitatively extracting electron and hole barrier heights, this approach refines the evaluation of intrinsic mobility and guides the optimisation of electrode interfaces, offering a robust framework for device design.

Black Phosphorus Field-Effect Transistor Technologies publication trend

The graph below shows the total number of articles in black phosphorus field-effect transistor technologies across all publications each year (not limited to Nature Index journals).

Technical terms

Field-effect transistor (FET): A semiconductor device in which an electric field applied to a gate electrode controls the conductivity of a channel between source and drain contacts.

Carrier mobility: A measure of how quickly electrons or holes can move through a semiconductor under an applied electric field, expressed in cm² V⁻¹ s⁻¹.

On/off ratio: The ratio of current flowing in the transistor’s on-state to that in the off-state, indicating switching efficacy.

Schottky barrier: An energy barrier formed at a metal–semiconductor interface that impedes carrier injection unless sufficient bias is applied.

Heterostructure: A layered assembly of dissimilar materials creating atomically sharp interfaces to tailor electronic and optical properties.

Subthreshold swing: The change in gate voltage required to modulate the drain current by one order of magnitude in the transistor’s subthreshold region, measured in mV dec⁻¹.

References

1. Black Phosphorus Field-Effect Transistors with Improved Contact via Localized Joule Heating. Nanomaterials (2023).
2. High-quality sandwiched black phosphorus heterostructure and its quantum oscillations. Nature Communications (2015).
3. High-performance n-type black phosphorus transistors with type control via thickness and contact-metal engineering. Nature Communications (2015).
4. Analysing black phosphorus transistors using an analytic Schottky barrier MOSFET model. Nature Communications (2015).
5. Temperature-stable black phosphorus field-effect transistors through effective phonon scattering suppression on atomic layer deposited aluminum nitride. Nanophotonics (2020).