NONLINEAR PIEZOELECTRIC EFFECT IN CDTE AND CDZNTE

Strained quantum wells (QWs) grown along the polar axis (111) in a zin c-blende semiconductor exhibit a piezoelectric field. This field stron gly modifies the energy of excitons confined in QWs. We have extracted , from optical measurements of excitonic transitions, the piezoelectri c field value in a large set of QWs: CdTe/CdZnTe, CdTe/CdMnTe, CdZnTe/ CdMnTe. By suitably choosing the composition of alloys, we have obtain ed different values of strains (compressive or extensive) due to the l attice mismatch between QWs and barriers. The non-linear piezoelectric effect appears clearly when plotting the piezoelectric tensor compone nt e14 versus lattice mismatch. For example e14 increases.from 0.07 C/ m2 to 0.15 C/M2 when the lattice mismatch varies from - 0.3% to - 1.7% .