Picosecond time-resolved two-dimensional ballistic electron transport.

Time-resolved transport of ballistic electrons in a two-dimensional electron gas has been measured with a resolution of less than 5 ps. This was accomplished by using picosecond electrical pulses to launch electrons from the emitter of a transverse magnetic focusing structure and optoelectronically sampling the collector voltage. Both plasma resonances and the ballistic transport signal are clearly resolved. The transit time appears to be somewhat longer than expected from simple Fermi velocity considerations.