ABSTRACT
ZnO thin-film piezoelectric transducers were integrated on GaAs ridge waveguides using RF-magnetron sputtering. Highly c-axis oriented and highly resistive ZnO films were successfully deposited on a GaAs substrate using a SiO2 thin buffer layer, which was introduced to alleviate a thermal mismatching problem between ZnO and GaAs. Stress on the cleaved facet of the waveguide was imaged with a spatially-resolved and polarization-resolved photoluminescence technique, and was compared with the simulation result. The results showed that the GaAs mesa is stressed up to 1 x 109 dyn/cm2 (10-3 strain) due to residual stress from the ZnO/SiO2/GaAs structure. Potential device applications are discussed that will utilize the intrinsic stress and the piezoelectric stress obtainable from the ZnO transducers.
