ABSTRACT

When electrons are confined within a semiconductor thin film with a thickness of the order of the

de Broglie wavelength, the wave nature of the electrons becomes important, thus quantum size and

tunneling effects will influence the optical and electronic properties of the material. In semiconductor

heterostructures, fabricated by stacking films of several compatible semiconductor materials with differ-

ent bandgaps, one can create almost arbitrary potential profiles. Suitable designs of semiconductor

heterostructures permit the observation of various tunneling effects, in particular resonant tunneling.

The principle of resonant tunneling has been known for a long time [1]. To realize semiconductor

resonant tunneling devices such as resonant tunneling diodes (RTDs), the control of the film deposition

with atomic layer thickness accuracy and the realization of semiconductor quantum well-superlattice

structures with planar and sharp heterointerfaces are essential prerequisites. These are warranted

by modern crystal growth technology such as molecular beam epitaxy (MBE) or chemical vapor

deposition (CVD).