NIST researchers have developed a new method to create single-atom transistors using quantum tunneling. The team, led by Richard Silver, used a scanning tunneling microscope to remove hydrogen atoms from a silicon chip, allowing phosphine gas to attach at specific sites. The resulting phosphorus atoms were then embedded into the silicon surface, creating the foundation for single-atom transistors.
The researchers found that applying heat during the fabrication process could disrupt the structure of the atomic-scale devices, so they developed a novel technique to make electrical contact with the buried atoms. By heating a layer of palladium metal applied to specific regions, they formed an electrically conducting alloy that naturally penetrated through the silicon and made contact with the phosphorus atoms.
The ability to control the flow of one electron at a time is crucial for creating quantum bits (qubits) that could be used in quantum computing. The NIST team demonstrated that they could precisely control the rate at which individual electrons tunnel through atomically precise tunnel barriers in single-electron transistors, opening up new possibilities for creating qubits.
The researchers published their findings in two papers: “Atomic-scale Control of Tunnel Coupling” in Communications Physics and “Atom-by-Atom Fabrication of Single and Few Dopant Quantum Devices” in Advanced Functional Materials.
Keywords: Tunneling, Transistors, Qubits, Quantum Mechanics, Atomically Precise
