The transistor that makes the modern computer memory possible works as an electronic switch. When there are no electrons on the transistor no current can flow and the transistor is turned off. When the voltage on a gate electrode is increased, electrons are added to the transistor and it turns on. In a collaboration between MIT and IBM it was recently discovered that very small transistors behave in a very unusual way. In contrast to conventional transistors which have only two possible states, either on or off, a very small transistor turns on and off again every time one electron is added to it by the gate. The single-electron behavior has so far been observed only at very low temperatures. In order to make devices that are potentially useful for electronic applications, a much higher temperature must be reached. The operating temperature is determined by the energy necessary to transfer an electron from one of its leads onto the transistor. The work proposed will isolate the parameters that determine this energy scale, making possible single-electron devices operating at practical temperatures. Experiments to test the ultimate speed of single-electron transistors are also planned.
