Papers by Author: J. Zavadil

Abstract: The preparation and characterization of thick InP layers by Liquid Phase Epitaxy with admixture of Ce, Tb, Dy and Yb in the growth melt is reported. Measurement of temperature dependent Hall affect, C-V characteristics and low-temperature photoluminescence show the change of n®p type conductivity and considerable improvement of structural and electro-optical parameters for all studied rare-earth elements. Mn was identified as dominant acceptor impurity in the case of Tb and Dy addition. In the case of Ce and Yb the dominant acceptor was identified as isoelectronic Ce or Yb on the In site subjected to a strong electron-lattice interaction. The reported high quality thick p-type InP layers could well be used for the preparation of radiation detector structures.

Abstract: The aim of this work is to study the new method of direct synthesis of lead and iodine as the input material of PbI2. This method has not been studied for this material till now, and seems to be one of the new methods for preparation of the input material. The photoluminescence measurement and measurement of resistivity has been done and compared with the measurements done by precipitation and zone purification.

Abstract: Binary and ternary TeO2 based oxy-chloride glass systems have been prepared and characterised by absorption and low-temperature photoluminescence spectroscopy, and by the measurements of dc electrical conductivity. Prepared glasses exhibit transmittance 75-80% in a broad transmission range 0.3 – 6.5µm with modest shift of upper absorption edge to longer wavelength as heavier ions are introduced into the system. Electronic transitions between 4f-4f inner shells of Pr3+ ions embedded into the host glass have been investigated in a wide temperature range as a function of used precursors used for doping. The temperature dependence of dc electrical conductivity exhibits Arrhenius plots with the single activation energy. PACS codes 81.05.Kf, 78.20.Ci, 78.55.Hx