Structural dependence of CsI(Tl) film scintillation properties

Scintillating CsI(Tl) films were obtained by vacuum deposition on single crystalline LiF substrates and non-orienting glass substrates. Their structure and morphology were examined by X-ray diffraction and scanning electron microscopy. Scintillation properties of films dependent on their structure are discussed

Surface morphology features of point contact gas sensors based on Cu-TCNQ compound

International audienc

Laser ablation and photostimulated passivation of the surface of Cd1–хZnхTe crystals

A new physical method of Cd1–хZnхTe-detectors passivation is proposed — the treatment of crystal surface by a laser ablation (LA) with subsequent photostimulated passivation (PhSP), during wich a high-resistance oxide layer is formed on it’s surface after the surface cleaning under intensive light irradiation effect. It is shown that the method of LA+PhSP is manufacturable and in comparison with PhSP and PhESP methods developed earlier provides a thick, homogeneous and high-oxide films, which significantly increases the surface resistivity of Cd1–хZnхTe samples and reduces leakage currents in them

Kinetics of Cr3+ to Cr4+ ion valence transformations and intra-lattice cation exchange of Cr4+ in Cr,Ca:YAG ceramics used as laser gain and passive Q-switching media

This paper focuses on the kinetics of Cr4+ formation in Cr,Ca:YAG ceramics prepared by solid-state reaction sintering. The kinetics of Cr4+ formation was studied by annealing of Cr,Ca:YAG ceramics in ambient air under different temperatures at different times, resulting in the transformation of Cr3+ to Cr4+. The activation energy (Ea) of Cr3+ oxidation determined by the Jander model was 2.7 ± 0.2 eV, which is in good correlation with the activation energy of innergrain oxygen diffusion in the YAG lattice. It is concluded that Cr3+ to Cr4+ transformation in YAG ceramics is limited by oxygen diffusion through the grain body. It was established that in Cr,Ca:YAG ceramics, the intralattice cation exchange, in which the Cr4+ ions exchange positions with the Al3+ ions, switching from "A" to "D" sites, is faster than Cr3+ to Cr4+ oxidation. In the temperature range of 900-1300 °C, the reaction enthalpy of Al3+/Cr4+ ion exchange between octahedral "A" and tetrahedral "D" lattice sites is close to zero, and this exchange ratio is thermodynamically driven by entropy