Observation of Surface Roughness by PAS using Transparent Transducer and Photothermal Deflection Sepectroscopy (PDS)

This paper is concerned with the experimental study of photoacoustic spectroscopy (PAS) using a transparent transducer and photothermal deflection spectroscopy (PDS). The amplitude and phase of PA and PD signals are observed for differen surface roughness (etched, polished, and roughed) of the example semiconducting CdS. There are no substantial differences between PAS and PDS. Additional signal increase caused by the damaged surface layers is observed at wavelength longer than the absorption edge. The phase signals reflect information of the depth and arc less affected by the noise.