Hot-electron transport processes in ballistic-electron emission microscopyat Au-Si interfaces

Ballistic-electron emission microscopy (BEEM) allows to study the transport of hot electrons in thin films and at buried interfaces with a lateral res olution in the nanometer range. In this review, the relevant transport proc esses are described in detail. For the particular case of the interface bet ween thin Au films and n-type Si(111), BEEM results are presented. In BEEM imaging, it is observed that the collector current increases when the tip i s located at terrace edges of the Au film. This effect demonstrates an impr oved matching of the populated electron states in the metal with the conduc tion-band states in the semiconductor in the case of electron injection at a terrace edge. It indicates a strong influence of the electronic structure of the metal on hot-electron transport as well as a predominant conservati on of lateral momentum at the interface. (C) 2000 Elsevier Science B.V. All rights reserved.