DPG Phi
Verhandlungen
Verhandlungen
DPG

Berlin 2008 – scientific programme

Parts | Days | Selection | Search | Downloads | Help

HL: Fachverband Halbleiterphysik

HL 51: Poster IV

HL 51.53: Poster

Thursday, February 28, 2008, 16:30–19:00, Poster D

Study of the solubility limits and secondary phase formation for ZnO:TM (TM = V, Fe, Co, Ni) mixed crystals by Raman spectroscopy — •Martin Koerdel1, Marcel Schumm1, Fabian Bach1, Huijuan Zhou2, Wojciech Szuszkiewicz3, Sven Mueller4, Carsten Ronning4, and Jean Geurts11Physikalisches Institut, Universität Würzburg, Am Hubland, 97074 Würzburg — 2Institut für angewandte Physik, Universität Karlsruhe — 3Polish Academy of Science, Warsaw — 4II. Physikalisches Institut, Universität Göttingen

For ZnO alloyed with transition metal (TM) ions the possibility of room temperature ferromagnetism is predicted if the TM ions occupy cation sites. To investigate the incorporation of various TM ions (V, Fe, Co, Ni) and to check their solubility limits in the ZnO crystal lattice we study the ZnO:TM and possible TM-oxide vibrations by Raman spectroscopy. Three ZnO:TM systems are compared: (i) layers prepared by sol-gel technique from nanocrystals, (ii) ion implanted layers and (iii) bulk crystals grown (900°C) by vapor phase transport. TM ion concentration ranges up to 20 at.%. An annealing sequence (700°C, 900°C) is applied to systems (i) and (ii). Each annealing step significantly improves the crystal order. Below the solubility limit the incorporation of the TM ions only activates symmetry-forbidden ZnO host lattice phonon modes proportional to the TM ion fraction incorporated in the ZnO lattice. No TM local vibration modes are observed. TM solubility limits are typically below 10% and, moreover, depend strongly on the sample growth method. TM-oxides are identified not only by their phonons but also by magnetic excitations.

100% | Mobile Layout | Deutsche Version | Contact/Imprint/Privacy
DPG-Physik > DPG-Verhandlungen > 2008 > Berlin