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Fotoelektrická spektroskopie hlubokých hladin ve vysoko- odporovém CdTe
Kubát, Jan ; Franc, Jan (vedoucí práce) ; Sopko, Bruno (oponent)
CdTe is one of the most interesting X-ray and g-ray detectors' material. This work deals with influence of deep levels to photoelectric properties of CdTe. PICTS, Lux-Ampere and spectral dependences measurements at room temperature and low temperature 10K were performed on one undoped and several variously doped (Cl, Sn and Ge) samples and applied electrical fields up to 800V.cm-1. Experimental setups are introduced. Room temperature numerical solution of sample photoelectrical properties for typical midgap level using driftdiffusion and Poisson equation was performed and results are discussed. The experimentally observed slopes of Lux-ampere characteristics and energy shifts of the main photoconductivity peak with the applied voltage are explained based on a model of screening of electric field by charge accumulated on deep levels. Finally comparison with acquired experimental data is performed yielding estimates of maximum total concentration of deep levels in the samples.
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Vliv žíhání na koncentraci přirozených defektů v polovodičích (CdZn)Te.
Bugár, Marek ; Belas, Eduard (vedoucí práce) ; Sopko, Bruno (oponent)
Práca je zameraná na výskum optimálních podmienok žíhania, ktoré vedú k výraznému zníženiu koncentrácie prirodzených defektov v polovodičoch (CdZn)Te. Požiadavky kladené na materiál (CdZn)Te používaný ako podložky pre tenké vrstvy (HgCd)Te tvorené epitaxiou z molekulárnych zväzkov sú kryštál s nízkou koncentráciou štruktúrnych defektov, vysoká priepustnosť žiarenia s vlnovou dĺžkou 10m a dobrá kryštálová štruktúra. Bol skúmaný vplyv žíhania na zmeny parametrov týchto požiadaviek pomocou optického mikroskopu pracujúceho v infračervenej oblasti, Fourierovským interferometrom pre strednú infračervenú oblasť a pomocou difraktometru metódou XRC. Bol skúmaný vplyv žíhania na vzorky obsahujúce telúrové inklúzie pri teplotách 600-850řC v parách kadmia. Bola tiež odmeraná zmena telúrových inklúzií po žíhaní v parách telúru. Bola skúmaná zmena morfológie inklúzií vo vzorkách s kadmiovými inklúziami po žíhaní pri teplotách 600-800řC v parách telúru, ako aj po žíhaní v parách kadmia.
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Fotoelektrická spektroskopie hlubokých hladin ve vysoko- odporovém CdTe
Kubát, Jan ; Franc, Jan (vedoucí práce) ; Sopko, Bruno (oponent)
CdTe is one of the most interesting X-ray and g-ray detectors' material. This work deals with influence of deep levels to photoelectric properties of CdTe. PICTS, Lux-Ampere and spectral dependences measurements at room temperature and low temperature 10K were performed on one undoped and several variously doped (Cl, Sn and Ge) samples and applied electrical fields up to 800V.cm-1. Experimental setups are introduced. Room temperature numerical solution of sample photoelectrical properties for typical midgap level using driftdiffusion and Poisson equation was performed and results are discussed. The experimentally observed slopes of Lux-ampere characteristics and energy shifts of the main photoconductivity peak with the applied voltage are explained based on a model of screening of electric field by charge accumulated on deep levels. Finally comparison with acquired experimental data is performed yielding estimates of maximum total concentration of deep levels in the samples.
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