The Department of Electrical Engineering

The tremendous progress by process engineers, semiconductor device physicists, and circuit designers in making better chips is the foundation upon which the computer revolution of the last decades has been built. The complexity of chips has been doubling every eighteen months, and their speed has been increasing by a factor of ten every five years. A key ingredient in this progress has been a deeper understanding of the physics of the materials and devices. The goal of my research is to advance the physical foundations of devices and develop new kinds of devices.

As devices have been made smaller, quantum effects have become important. These effects already influence the operation of commercial devices. We are investigating new device designs, which will take advantage of quantum mechanical processes to provide a route to further device scaling and performance improvements. For example, “quantum dots” – a few hundred or thousand molecules of one material embedded in another – exhibit a range of useful properties for new types of semiconductor emitters and detectors.

An important component of our research is directed towards developing fully quantum-coherent devices as needed for quantum information processing. While quantum computation theoretically provides revolutionary advances, the physical realization will be exceptionally challenging. Our major emphasis has been on demonstrating ways to use the spin of an electron as a quantum bit (qubit). For example, we have found that the quantum coherence of electron’s spins in a silicon crystal can be preserved for almost a second, two or three orders of magnitude larger than has been measured in other materials.