• aluminium
• cobalt
• continuous growth
• design of experiment
• Doehlert design
• magneto-optics
• nanoparticles
• Plackett-Burman
• plasmonics
• zinc

This thesis work is focused on the design and preparation of doped semiconductors in the form of colloidal nanoparticles (NPs), prepared by continuous growth approach, which involves the continuous injection of metal oleate complexes into a hot oleyl alcohol solution. ZnO doped with cobalt was chosen because carrier-mediated magnetic coupling between Co2+ cations in ZnO films has been observed in previous works, leading to room temperature ferromagnetism.
In highly doped semiconductors NPs, charge carriers can be introduced through insertion of aliovalent cations in the lattice. To this purpose Al is selected as electron donor dopant, resulting in carrier densities lower than metals, thus shifting the plasmonic resonance in the infrared range while maintaining transparency in the visible range.
The co-doping with different cations is interesting for magnetoplasmonics, as it makes possible to achieve magnetic and plasmonic properties in the same NPs. In the synthetic strategy there are some challenges that require optimization of the synthetic parameters to achieve control on the final properties of the NPs, such as size, dopant incorporation and optical properties.
To optimize the synthetic method, a design of experiment approach (DoE) was used to correlate the synthetic conditions with the NPs features obtained with various characterization techniques. As a result of the optimization, some of the parameters of the final NPs were improved, for example we have reached high doping efficiencies with aluminium. Magnetic circular dichroism spectroscopy was used on some selected samples, to study the magnetic and magneto-optical properties of the co-doped NPs.