Future Prospects and Possible Applications

Abstract

In this chapter, we discuss possible device applications of Bloch oscillations and other high-field transport phenomena in semiconductor superlattices. We have to admit that this may seem to be a rather far-fetched discussion, since no such applications have been realized yet. Nevertheless, it seems to be worth discussing some basic issues in this field since, in the author’s opinion, there is no doubt that there is a need for such devices, even if it is “only” a need for a tunable THz source for scientific spectroscopy. However, it remains to be seen whether there will be broad applications, for example Bloch emitters for high-speed free-space communications or for imaging in the THz range.

In the following, we shall first discuss some general issues involving the use of coherent electronic transport effects for device applications. Then, we shall specifically address the question of gain in semiconductor superlattices, which is a prerequisite for an electrically pumped source. Finally, we shall briefly address some possible device schemes.