Transistor Created by Single Electron

A University of Pittsburgh-led team has created a single-electron transistor which can act as a building block for powerful computer memories, advanced electronic materials and quantum computers.

The transistor's central component consists of only one or two electrons of 1.5 nanometers in diameter. That flexibility would make the transistor important to a range of computational applications, from memories to quantum processors, powerful devices.

In addition, the tiny central island could be used as an artificial atom for developing new classes of artificial electronic materials, such as exotic superconductors with properties not found in natural materials, explained.

Scientist cited their device as SketchSET, or sketch-based single-electron transistor. Using the sharp conducting probe of an atomic force microscope, electronic devices such as wires and transistors of nanometer dimensions can be created at the interface of a crystal of strontium titanate and a 1.2 nanometer thick layer of lanthanum aluminate. The electronic devices can then be erased and the interface used anew.

The SketchSET -- which is the first single-electron transistor made entirely of oxide-based materials -- consists of an island formation that can house up to two electrons. The number of electrons on the island -- which can be only zero, one, or two -- results in distinct conductive properties. Wires extending from the transistor carry additional electrons across the island.

One of the advantages of a single-electron transistor is its extreme sensitivity to an electric charge. Another property of these oxide materials is ferroelectricity, which allows the transistor to act as a solid-state memory. The ferroelectric state can, in the absence of external power, control the number of electrons on the island, which in turn can be used to represent the 1 or 0 state of a memory element. A computer memory based on this property would be able to retain information even when the processor itself is powered down, researcher commented. The ferroelectric state also is expected to be sensitive to small pressure changes at nanometer scales, making this device potentially useful as a nanoscale charge and force sensor.