Rectifying behavior in twisted bilayer black phosphorus nanojunctions mediated through intrinsic anisotropy

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Van der Waals bonded heterostructures offer unique electronic properties.
• Bilayer black phosphorus (BP) is a promising 2D material for nanoscale applications.
• Anisotropy in 2D materials can be leveraged for novel device functionalities.

Purpose of the Study:

• To explore bilayer black phosphorus (BP) heterostructures for nanoscale devices.
• To investigate the electronic and quantum transport properties of AA stacking and 90° twisted BP nanojunctions.
• To understand how BP's anisotropic properties influence current characteristics.

Main Methods:

• Density functional theory (DFT) calculations were employed to study electronic properties.
• First-principles simulations combined with the non-equilibrium Green's function (NEGF) approach were used for quantum transport calculations.
• Analysis of interlayer direction-dependent current characteristics in various nanojunction configurations.

Main Results:

• The electronic properties of AA stacking and 90° twisted bilayer black phosphorus were characterized.
• Quantum transport properties of homogeneous BP nanojunctions were calculated, highlighting anisotropic effects.
• A 90° twisted BP nanojunction demonstrated potential as a rectifier without p-n junction characteristics.
• Asymmetric tunneling between armchair- and zigzag-directional BP sheets was identified as the mechanism for rectification.

Conclusions:

• Van der Waals bonded bilayer black phosphorus heterostructures are suitable for nanoscale device applications.
• The intrinsic anisotropy of bilayer black phosphorus enables rectification in twisted nanojunctions.
• Exploiting material anisotropy offers a pathway for designing advanced electronic devices.