Band alignment

The term band alignment refers to the electronic structure when 2 (or more) materials join at a point. We split these into three categories, based on whether each material is a metal or semiconductor/insulator.

The simple theory of the band alignment of:

a) semiconductor/semiconductor junctions.

b) metal/semiconductor junctions.

c) metal/metal junctions.

It is worth emphasising this topic combines two theories awkwardly. The bulk band structure is a result of a periodic infinite crystal. The joined material (referred to as a heterostructure or junction) is normally considered strictly aperiodic, with the two halfs (material A and material B) being considered to continue to infinity.