PHOTOACOUSTIC EFFECT OF PIEZOELECTRIC ZNO THIN-FILMS

This paper describes the photoacoustic (PA) effect of piezoelectric Zn O thin films. The one-dimensional theory of the PA-effect was derived. The relationships between PA-signals and modulation frequency, thin f ilm properties such as piezoelectric coefficients, dielectric constant , specific heat and thermal conductivity coefficient were obtained. Th e experimental results on the PA-effect of sputter-deposited ZnO thin films exhibited good agreement with the theoretical analysis. The piez oelectric stress coefficients, e(33) and e(31), of some ZnO films were determined from the PA-signals, typical values of which are 0.82 C/m( 2) and -0.43 C/m(2), respectively.