Piezoelectric effects in strained layer heterostructures grown on novel index substrates

Abstract

III–V and II–VI semiconductors are piezoelectric and therefore electric fields can be generated in strained layer heterostructures formed from these materials. The strain induced electric fields depend on the symmetry of the strain, which in turn depends on the orientation of the substrate on which the heterostructure is grown. For strain generated electric fields to occur in a zincblende structure semiconductor, the strain must distort the angles of the cubic unit cell away from 90°. Strains in (100) oriented heterostructures do not distort the 90° angles of the cubic unit cell and no electric fields are generated. However, for other substrate orientations, electric fields can be generated in the strained layers. These electric fields can lead to large changes in the optical properties of the heterostructure which can be externally. modulated to.make, for example, electro-optic devices. They can also cause charge accumulation which can be used in field effect transistor and resonant tunneling structures.