molecular beam epitaxy

Syllable breakdown

Dictionary meaning

a highly controlled thin-film deposition technique in which beams of atoms or molecules are directed at a heated crystalline substrate in ultra-high vacuum — pressure below 10⁻¹⁰ torr — where they land, migrate to energetically favourable sites, and form an epitaxial — crystallographically aligned — thin film one atomic or molecular layer at a time; the ultra-high vacuum environment eliminates contamination, and the slow deposition rates allow atomic-layer control of composition and doping profiles; MBE is used to grow the quantum well and superlattice structures that underlie semiconductor lasers, high-electron-mobility transistors used in mobile communications, quantum dot arrays, and topological insulator thin films studied for quantum computing; in-situ monitoring techniques including reflection high-energy electron diffraction allow real-time observation of the growing surface during deposition

Examples

• Molecular beam epitaxy was used to grow the quantum well heterostructures at the heart of blue LED devices.
• MBE-grown topological insulator thin films exhibit surface states with spin-momentum locking that may enable dissipationless electronics.

Synonyms: MBE