RUI: Ultrafast Terahertz Spectroscopy of Carrier Dynamics in Semiconductors

Macalester College, Saint Paul MN

Investigators

Abstract

This individual investigator award will support research in ultrafast optics and semiconductor physics. As switching rates in electronic devices are pushed to ever higher frequencies, it becomes increasingly important to understand carrier transport phenomena in semiconductors on picosecond and femtosecond time-scales. Using ultrafast terahertz spectroscopy it is possible to impulsively excite a semiconductor with a femtosecond optical pulse or single-cycle electromagnetic pulse, and record the resulting motion of charge in time. This project, at a predominately undergraduate institution, will use these techniques to investigate charge transport and hot-carrier phenomena in semiconductors and semiconductor heterostructures on time-scales that will be relevant to future devices. One focus of research will be to investigate hot carrier phenomena in semiconductors using ultrafast terahertz spectroscopy in a magnetic field. The second project will use ultrafast terahertz spectroscopy to study coherent intersubband phenomena in semiconductor quantum wells. The undergraduate researchers involved with this project will obtain training in state of the art techniques. This grant will support research in ultrafast optics and semiconductor physics at a predominately undergraduate institution. As computers and other electronic devices become ever faster, it becomes increasingly important to understand the flow of electrical current in semiconductors and other electronic materials on time-scales of a trillionth of a second or less. This project will use femtosecond light pulses to excite bursts of current in semiconductors, and will record the evolution of the current pulses in time by recording the electromagnetic waves they emit. The project goal is to study the scattering of electrons and coherent phenomena in semiconductor devices. This will be relevant to the development of electronic technology. The undergraduate researchers involved with this project will obtain training in state of the art techniques.