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Studium elektrického pole v detektorech záření pomocí Pockelsova jevu / Studium elektrického pole v detektorech záření pomocí Pockelsova jevu

Study of electric field in radiation detectors by Pockels effect (Master Thesis) by Michael Hakl Abstract Cadmium Telluride (CdTe) is a convenient candidate for room tem- perature detection of X-ray and gama radiation due to 1.5 eV band- gap energy and high atomic mass. Since CdTe has the highest linear electro-optical coefficient among II-VI compounds, the detector rep- resents a Pockels cell. Transmittance of the crystal is modulated by the internal electric field. Processing of infrared camera photographs results in an electric field profile between biasing electrodes. The elec- tric field in semi-insulting CdTe is influenced with deep level traps causing charge polarization under the electrodes. Occupation of traps is dependent on metal-semiconductor interface. Relation of charge accumulation and band bending for gold and indium contacts was studied. Repolarization/depolarization induced by additional illumi- nation with sub/above bandgap excitation laser was observed and ex- ploited for determination of the deep level energy. Results obtained by the Pockels-effect method were supported with luminescence measure- ments. Correlation between the occurrence of deep levels and surface point defects was discovered. Keywords: Pockels electro-optical effect, Cadmium Telluride ra- diation detector, Electric field, Schottky...

Identiferoai:union.ndltd.org:nusl.cz/oai:invenio.nusl.cz:336601
Date January 2014
CreatorsHakl, Michael
ContributorsFranc, Jan, Richter, Ivan
Source SetsCzech ETDs
LanguageEnglish
Detected LanguageEnglish
Typeinfo:eu-repo/semantics/masterThesis
Rightsinfo:eu-repo/semantics/restrictedAccess

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