Experimentelle Untersuchungen zu Mechanismen von druck- und temperaturinduzierten Phasenübergängen
Experimental examinations of mechanisms of pressure- and temperature-induced phase transitions
von Nina Katrin Pukallus
Datum der mündl. Prüfung:2020-10-22
Erschienen:2021-10-18
Betreuer:Dr. Heidrun Sowa
Gutachter:Dr. Heidrun Sowa
Gutachter:Dr. Helmut Klein
Gutachter:Prof. Dr. Sharon Webb
Dateien
Name:PhD.pdf
Size:21.9Mb
Format:PDF
Description:Dissertation
Zusammenfassung
Englisch
Under the influence of pressure and/or temperature changes, crystalline materials undergo a phase transition. The directions of the crystalline unit cell before and after the phase transition can show orientation relations. These orientation relations can give clues about the atomar transition mechanism, which is expressed in group-subgroup relations via a common subgroup of both end configurations. The behaviour of crystalline materials during their phase transition was experimentally studied using synchrotron radiation and a diamond anvil cell respectively a graphite band-heated oven. The following five materials were used: indium arsenide, cadmium sulfide, cadmium selenide, copper indium diselenide and nickel sulfide. For the pressure-induced phase transition of indium arsenide no transformation path with a common subgroup could be found, but the orientation relations between high-pressure and low-pressure phase could be determined and the atomar mechanism of the transition could be derived. The orientation relations between the high-pressure and low-pressure phase of copper indium diselenide pointed to multiple possible transition paths. For the pressure-induced phase transition of cadmium sulfide and cadmium selenide, already assumed orientation relations and their correlating transition path could be confirmed. For the temperature-induced phase transition of nickel sulfide also an already assumed transition path could be confirmed, but no transition path via a common subgroup.
Keywords: crystallography; phase transitions; orientation relations; semiconductors; indium arsenide; copper indium diselenide; cadmium sulfide; cadmium selenide; nickel sulfide; synchrotron radiation; diamond-anvil cell
Schlagwörter: Kristallographie; Phasenübergang; Orientierungsbeziehungen; Halbleiter; Indiumarsenid; Kupfer-Indium-Diselenid; Kadmiumsulfid; Kadmiumselenid; Nickelsulfid; Synchrotronstrahlung; Diamantstempelzelle