4.5 SiGe heterojunctions and band offsets

When two semiconductors are joined at a heterojunction, discontinuities occur in the valence bands and in the conduction bands. For an atomically abrupt interface, these discontinuities are sharp on an atomic length scale (i.e. on the order of a few atomic distances). This is in contrast with band-bending effects, which are associated with depletion layers, and which occur on much larger length scale