Photoacoustic spectroscopy characterization of CdSe quantum rods

The optical absorption properties of as prepared CdSe quantum rods (QRs) are measured by the photoacoustic (PA) method. CdSe QRs were fabricated by the chemical solution deposition (CD) technique. Decreasing the rod size (width and length) that is determined by scanning tunneling microscope (STM), causes blue-shift of the PA spectra that can be clearly observed. The exciton energy of the CdSe QRs as estimated using the effective mass approximation (EMA) model and the dimensions determined by STM shows a reasonable agreement with that predicted by the PA measurements. The exciton energies calculated by EMA model show deviations from the experimental data for samples having smaller diameters. The thermal diffusivity of samples of different sizes shows an increase by at least an order of magnitude than the bulk value.