MOLECULAR-BEAM EPITAXY OF ZNCDSE ZNSE STRAINED-QUANTUM-WELL STRUCTURES ON GAAS(111)A SUBSTRATES AND PIEZOELECTRIC PROPERTIES/

We grew Zn0.8Cd0.2Se/ZnSe strained quantum-well structures on GaAs(1 1 1)A substrates 10 degrees-misoriented toward [1 0 0] direction by mol ecular beam epitaxy. The growth rates and the Cd composition in the Zn CdSe epilayers on (1 1 1)A substrates were small compared to those on (1 0 0) substrates at the same growth conditions. Therefore, in order to compare(1 1 1) and (1 0 0) samples with the same structures, these were grown separately. The piezoelectric properties were characterized by photoluminescence measurements at 11 K. The emission energies of t he (1 1 1) quantum wells shifted toward lower energy compared to those of the (1 0 0) quantum wells with the same well width, owing to the p iezoelectric effect. We calculated the internal electric field of thes e samples to be 0.9 x 10(7) V/m. The difference from the theoretical v alue (1.9 x 10(7) V/m) was discussed. The emission intensities decreas ed with increasing well width. We observed the screening of the piezoe lectric field by the photogenerated carriers. (C) 1998 Elsevier Scienc e B.V. All rights reserved.