Nanowerk reports that Australian researchers have created a quantum dot of just seven atoms that acts as a transistor.
The Age reports that Michelle Simmons, co-author, said the achievement marked the first time scientists had been able to dictate the placement and behaviour of single atoms within a transistor. “We’re basically controlling nature at the atomic scale,” she said. “This is one of the key milestones in building a quantum computer.”
The Centre for Quantum Computer Technology (CQCT) team is making devices with 4 nanometer features.
A defining feature of modern CMOS devices and almost all quantum semiconductor devices is the use of many different materials. For example, although electrical conduction often occurs in single-crystal semiconductors, gates are frequently made of metals and dielectrics are commonly amorphous. Such devices have demonstrated remarkable improvements in performance over recent decades, but the heterogeneous nature of these devices can lead to defects at the interfaces between the different materials, which is a disadvantage for applications in spintronics and quantum information processing. Here we report the fabrication of a few-electron quantum dot in single-crystal silicon that does not contain any heterogeneous interfaces. The quantum dot is defined by atomically abrupt changes in the density of phosphorus dopant atoms, and the resulting confinement produces novel effects associated with energy splitting between the conduction band valleys. These single-crystal devices offer the opportunity to study how very sharp, atomic-scale confinement—which will become increasingly important for both classical and quantum devices—influences the operation and performance of devices.