Scientists have created a single-atom transistor. Such devices may enable a new generation of computers with an unprecedented high memory capacity and power. This is stated in a study by scientists from the National Institute of Standards and Technology (NIST), whose work is published in the journal Advanced Functional Materials.
Researchers were able to create devices the size of one atom, and then produce a series of single-electron transistors with atomic control of the scale of the geometry of the device.
In their study, scientists have shown that they can precisely control the rate at which individual electrons flow through a physical gap or electrical barrier in a transistor – even if classical physics forbids electrons to do this because they lack energy. This strictly quantum phenomenon, known as quantum tunneling, becomes possible only when the gaps are extremely small – for example, in miniature transistors.
Atomic-scale control of tunnel coupling is a key property of atom-based quantum devices since it affects the ability to create quantum entanglement.
For the manufacture of monatomic transistors, scientists used a technique in which a silicon chip is coated with a layer of hydrogen atoms that easily bind to silicon. Using the thin tip of a scanning tunneling microscope, the researchers then removed hydrogen atoms at selected sites. The remaining hydrogen acted as a barrier.
“Since quantum tunneling is fundamental to any quantum device, including the construction of qubits, the ability to control the flow of one electron at a time is a significant achievement. We believe that our advanced method provides more stable and accurate atomic-scale devices. This is a difficult process, but we have outlined the steps so that other teams do not have to act by trial and error”.
Xiqiao Wang, lead author of the research
- Xiqiao Wang, Jonathan Wyrick, Ranjit V. Kashid, Pradeep Namboodiri, Scott W. Schmucker, Andrew Murphy, M. D. Stewart, Richard M. Silver. Atomic-scale control of tunneling in donor-based devices. Communications Physics, 2020; 3 (1) DOI: 10.1038/s42005-020-0343-1
- Jonathan Wyrick, Xiqiao Wang, Ranjit V. Kashid, Pradeep Namboodiri, Scott W. Schmucker, Joseph A. Hagmann, Keyi Liu, Michael D. Stewart, Curt A. Richter, Garnett W. Bryant, Richard M. Silver. Atom‐by‐Atom Fabrication of Single and Few Dopant Quantum Devices. Advanced Functional Materials, 2019; 29 (52): 1903475 DOI: 10.1002/adfm.201903475