Dana Vasiljević-Radović

Photoacoustic and Optical Properties of Zinc-Stannate Thin Films

Thin films of single-phase zinc-stannate (Zn2SnO4) were grown by rf magnetron sputtering onto glass substrates. Transmission in the visible range was measured allowing determination of the energy gap and thickness of analyzed thin film samples using interference fringes. The photoacoustic phase and amplitude spectra of all samples were measured as a function of the laser beam modulating frequency using a transmission detection configuration. Fitting of experimental data enabled calculation of thermal diffusivity, the coefficient of minority carrier diffusion, their mobility and lifetime.

Microstructural Properties of PZT Thin Films Deposited on LaNiO3-Coated Substrates

The modified polymeric precursor method (Pechini method) was successfully used for the preparation of epitaxial and polycrystalline ferroelectric Pb(Zr0.52Ti0.48)O3 (PZT) thin films. Films were deposited on LaNiO3 (LNO) – coated silicium (1 0 0) and platinum substrates (Pt (1 1 1)/Ti/SiO2/Si) by spin coating technique. LNO electrodes were also prepared by the Pechini method and treated under different thermal treatment conditions to obtain films with different structural and microstructural properties. Investigation of PZT microstructure was performed as a function of orientation and morphology of the bottom electrode, as well as of thermal treatment conditions. Grain size and morphology were analyzed by AFM, while the quality and orientation of PZT films were determined by GIXRD analysis. It has been found that the proposed thermal treatment on a hot plate, with slow heating rate and long annealing time, can result in the formation of epitaxial PZT films on Si and LNO-coated Si substrates.

Infrared properties of sintered α-MnSe

Abstract Far-infrared reflection spectra of sintered α-MnSe were measured at room temperature. The measured spectrum had one pronounced peak in accordance with literature data and group theory estimation and one smaller peak resulting from the applied sintering procedure. The measured reflection spectrum was analyzed using Kramers–Kronig analysis and a three-component effective medium model based on Bruggemans theory assuming the presence of a small amount of pores, dominant crystalline grains and intergranular material. In the model the crystalline grains were modeled as a single oscillator appropriate to the single crystal and the intergranular material was also defined as a single ionic oscillator.

Photoacoustic Properties of Single Crystal NiO

Thermal and electron transport properties of NiO single crystal were determined using the photoacoustic frequency transmission technique. Thermal diffusivity, coefficient of carrier diffusion, their lifetime, and the front and rear recombination velocity were calculated by comparing the experimental results with the theoretical photoacoustic amplitude and phase signals. As far as we know, no photoacoustic measurements on NiO samples have been made by now.