Chapter 3 - Electronic states in GaAs-AlAs short-period superlattices: Energy levels and symmetry

Abstract

The problem of conduction band minimum (CBM) in SPSLs has attracted wide experimental and theoretical attention for about 15 years; now it is at a full stop. To solve this problem, nearly all experimental and theoretical methods (as a Chinese proverb says, 18 sorts of arms) were used. In the process the conclusion becomes more and more definite, at the same time the material quality and the experimental and theoretical methods are improved dramatically. Many physical properties of short-period superlattices (SPSLs) can be used to design and fabricate devices, for example, super-high-frequency devices, mid-infrared and terahertz laser and light-emitting devices, and so on. But there is still a long way to go. In this process an elaborate energy band engineering design based on the accumulated physical knowledge is needed, and some new phenomena and problems are explored in this chapter.