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LPE Growth of III-V Semiconductors from rare-earth Treated Melts
Grym, Jan ; Procházková, Olga ; Zavadil, Jiří ; Žďánský, Karel
We focus on the characterization of InP and InGaAsP layers prepared by liquid phase epitaxy with rare-earth admixtures. We applied photoluminescence spectroscopy (PL), capacitance-voltage measurements, and secondary ion mass spectroscopy in order to explain: (i) the gettering effect and conductivity crossover of InP layers for Pr treated samples, (ii) narrowing of the PL and elecroluminescent spectra of the active InGaAsP region of a double-heterostructure LED.
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Films of Metal Nanoparticles Deposited on Semiconductors by Electrophoresis: Technology and Characterization
Žďánský, Karel ; Zavadil, Jiří ; Kacerovský, Pavel ; Kostka, František ; Lorinčík, Jan ; Černohorský, O. ; Fojtík, A. ; Müller, M. ; Kostejn, M.
Layers of nanoparticles in micelle enclosures were deposited on InP substrates by electrophoresis from isooctane colloid solutions containing Pd or Ag nanoparticles. The layers were investigated by SIMS, low-temperature photoluminescence spectroscopy and topography, absorption spectroscopy, Raman spectroscopy and sensitivity to hydrogen. Photoluminescence of InP was enhanced by the layers of Pd or Ag nanoparticles. Schottky barriers made on the n-type InP with layers containing Pd nanoparticles showed significant sensitivity to hydrogen in contrast to those containing Ag nanoparticles.
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Autofluorescenční spektroskopie plicní tkáně
Votruba, J. ; Zavadil, Jiří ; Javorský, Stanislav ; Kostka, František ; Klimtová, E. ; Brůha, T.
In-vivo investigation of bronchial tissue by autofluorescence (AF) spectroscopy is reported. The study demonstrates differences of both the spectral shape and of signal intensity in photoluminescence spectra emitted from tissue affected by carcinoma as compared to healthy bronchial mucosa. It turns out that point measurements of AF spectra significantly increase the diagnostic utility of the AF method in discrimination of malignant and benign tissue as compared to commercial AF imaging systems.
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Růst InP metodou LPE s přídavkem prvků vzácných zemin do taveniny
Grym, Jan ; Procházková, Olga ; Zavadil, Jiří ; Žďánský, Karel
Addition of REs to the growth melt is known to have purifying effect on AIIIBV LPE layers. Each member of REs family acts in its own way. Small addition of Tb, Dy, Tm, and Pr leads to pronounced gettering of shallow donors, the high purity n-type InP can be grown. Exceeding certain concentration, reversal of conductivity type from n to p occurs. Addition of Tm during growth on InP:Fe substrates always results in the preparation of semi-insulating layers due to Fe out-diffusion mediated by RE admixture.
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Preparation and characterisation of chalcogenide glasses
Ležal, Dimitrij ; Zavadil, Jiří ; Poulain, M.
Chalcogenide glasses systems AS-S, As-Se, As-S-Se and Ge-Se-Te have been prepared and characterised by absorption spectroscopy, scanning electron microscopy and photoluminescence. Photoluminescence spectra have been measured in wide temperature range and the role of multiphonon transitions in mediating the inner 4f-4f electronic transitions was demonstrated. Peculiar Pr related band at 1600 nm has been found in some samples.
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