Prøveforelesning
Se prøveforelesningBedømmelseskomité
Professor Andre Venter, Nelson Mandela Metropolitan University, Port Elizabeth
Førsteamanuensis Maria Ganchenkova, Helsinki University of Technology
Førsteamanuensis Ola Sveen, Universitetet i Oslo
Leder av disputas: Professor Einar Sagstuen
Veileder: B. G. Svensson og A. Y. Kuznetsov
Sammendrag
During this research project conducted at MiNaLab/Center for Material Science and Nanotechnology of the university of Oslo under supervision of prof. B. G. Svensson metal contacts to ZnO have been investigated. A novel method to achieve good quality rectifying metal contacts, i.e. contacts with a diode-like behavior, has been found and studied. ZnO is a promising material for the realization of high efficiency white light emitters for substituting light bulbs in general illumination, ultra violet emitters, high temperature and transparent electronics. Moreover, ZnO already plays a key role in some of the solar cells commercially available as it is used as transparent conducting layer on top of them to collect the electricity produced in the solar cell by the incoming sun light.
All these present and possible applications need a proper mastering of the metal contacts to the material to electrically access the device. In detail, contacts with both rectifying properties and ohmic characteristics, i.e. with no dependence on the polarity applied, are needed from a technological point of view. However nowadays, this represents, still, a challenging issue in case of ZnO. During this research project it has been found that by simply dipping ZnO in hydrogen peroxide kept at room temperature Palladium contacts turn from ohmic to rectifying. In addition, this finding has been used to study the effects of impurities, commonly present in ZnO, like Lithium and Aluminium, on the electrical characteristics of the material with the purpose to understand and improve ZnO material properties for the interesting application above mentioned.
Kontaktperson
For mer informasjon, kontakt Christine Sundtveten.