Lateral currents in ballistic electron emission microscopy

Lateral currents flowing in metal overlayers in ballistic electron emission microscopy are studied theoretically. Current distributions in thin metal overlayers are complicated due to the multiple reflection by vacuum and Schottky barriers. However, when the thickness is larger than about 50 A° , the distributions are almost the same as those of free electron beams in semi-infinite metal surfaces. With variation of the metal-overlayer thickness, transmission probability shows resonance structures. At peaks of the resonances, the probabilities are larger than that of the limit of the infinite thickness. This result is explained by a transverse resonant tunneling. Momentum conservation in the ballistic transport of the lateral currents is also discussed. q1999 Elsevier Science B.V. All rights reserved