3-DIMENSIONAL TUNNELING IN QUANTUM BALLISTIC MOTION

We provide an elementary case study of field-induced quantum tunneling in a realistic three-dimensional environment which exhibits both tunn eling and classically allowed motion. An analytic description is prese nted for ballistic motion in a uniform electric field. From there we d erive simple expressions concerning the wave function for field emissi on from an ultrathin quantum well in the tunneling limit. At the same time a wave-packet description of the tunneling process is obtained. T he tunneling time can be read off from the lateral spread of the tunne ling current distribution. (C) 1998 American Association of Physics Te achers.