Optical study of the piezoelectric field effect in (1 1 1)-oriented CdTe/CdMnTe strained quantum wells

We report on low-temperature reflection, transmission and photoluminescence studies of (1 1 1)-oriented CdTe/ Cd 1− x Mn x Te ( x ≈ 0.16) strained quantum wells grown on nominal and vicinal Cd 0.95Zn 0.05Te substrates by molecular beam epitaxy. Only samples grown on vicinal substrates are twin-free and exhibit very sharp optical lines, making possible a quantitative study of exciton transitions. Analysis of the exciton transition energy and oscillator strength as a function of quantum well width provides unambiguous optical evidence of a piezoelectric field F ≈ 0.8 × 10 5 V/cm in quantum wells strained by ∼ -0.4%. Observations of exciton absorption in piezoelectric multiple quantum wells up to 80 K will also be reported for the first time.