Baran Yildirim
PhD Student
Telephone: +61 2 6268 8923
Fax: +61 2 62688017
Email: b.yildirim@student.adfa.edu.au
Location: PEMS Nth, Room 204
Field of Study - Physics/Photonics
Supervisor: Assoc. Prof. Hans Riesen
Co-Supervisor: Assoc. Prof. Glen Stewart
Research Topic - Optical properties of transition metal ions in nanocrystalline wide-band gap semiconductors
In general, the aim of the study is to understand the optical and electronic properties of transition metal ions in wide-band gap semiconductors as a function of crystallite size. We started to examine some optical properties of Co2+ ions in LiGa5O8 nanocrystalline powders; there are both octahedral and tetrahedral sites in this lattice. It is assumed that the Co2+ ions can enter the crystal lattice in both sites during the combustion reaction. In order to validate this and understand the charge transfer mechanism, spectral hole-burning studies were performed in nano-powders and single crystals. The nanocrystals are to be examined in different hosts such as glasses and glass ceramics. Additionally, XANES (X-Ray Absorption Near Edge Structure) and XAFS (X-Ray Absorption Fine Structure) measurements are to be done at the Australian Synchroton in order to quantify the Co2+ ions in tetrahedral and octahedral sites. This material has some potential for photovoltaic applications; one of our motivations for this research project. We will continue conducting a systematic study of the optical properties of a range of transition metal ions incorporated into oxide nanocrystals.
