Papers by Keyword: Ba_xSr_1-xTiO₃

Abstract: Ferroelectric thin film devices have been demonstrated using Ba_xSr_1-xTiO₃ (BST) as a light intensity detector. Various compositions of BST (x=0.7, 0.8 and 0.9) were prepared using Chemical Solution Deposition method. Solution of barium acetate, strontium acetate, titanium (IV) iso-propoxide in a mixture of acetic acid and ethylene glycol was spin-coated onto a silicon substrate. The BST film was annealed at 800°C. The microstructure and the crystalline characterization of BST were studied using X-Ray Diffraction (XRD) pattern with General Structure Analysis System (GSAS) refinement. The film thickness was measured using Scanning Electron Microscopy (SEM). The response of BST film to source of light intensity was investigated with IRC meter and resonator coupling. The results show that the resistance of a thin BST film decrease as the intensity of light increase. On resonator coupling, V_OUT shows a slight increases as the intensity of light increases.

Abstract: Pulse modulated double hollow cathode RF plasma jet system with two separate independent nozzles made of BaTiO3 (BTO) and SrTiO3 (STO) was used for deposition of BSTO thin films on Si and on multi-layer Si/SiO2/TiO2/Pt substrates. Dielectric properties of BSTO layers strongly depend on ratio composition expressed by parameter x = Ba/(Ba+Sr) and on accuracy in presence of other elements. Space resolved optical emission spectroscopy (OES) was used mainly for monitoring of concentration of particles sputtered from the hollow cathode and for feedback correction of power supplied in both nozzles because applied power was responsible for sputtering speed of Ba and Sr particles. Main attention was focused on relation between ratio of spectral intensity of Ba, Ba+, Sr and Sr+ lines close to substrate and ratio of Ba and Sr concentration in the deposited film. 2D map of emission lines intensity distribution for Ba, Ba+, Sr, Sr+, Ti, Ar, and Ar+ for double hollow cathode plasma jet system with BTO and STO nozzles was created. OES was also used for observing of excess of Ti particles in final layer with negative effect on layer properties and for measurement of rotational temperature of OH radicals. Preliminary results of all these optical measurements are published in this paper. Deposited thin films were analyzed by X-ray diffraction, which confirmed presence of BSTO and STO perovskite phase in the films, by atomic force microscopy (AFM), by electron microprobe and by micro-Raman scattering measurement.