TRANSIENT SIMULATION OF ELECTRON-EMISSION FROM QUANTUM-WIRE STRUCTURES

We model a GaAs quasi-one-dimensional quantum wire in an applied longitudinal field and focus on mechanisms of electron emission leading to real-space transfer from the wire. The Monte Carlo simulation assumes an initial electron distribution in the wire and calculates the time required for electrons to undergo nonequivalent intervalley scattering to three-dimensional states. The model includes multiple subbands, polar optic and acoustic phonons, intervalley scattering, and band-structure nonparabolicity. Results have been obtained for different confinement conditions as well as different temperatures. We find that the required time is a very strong function of the longitudinal field and ranges from 4 ns down to 1 ps for fields in the range of 100 V/cm to 8 kV/cm. The corresponding distances in the wire vary from 130-mu-m down to the submicrometer range.