Fiona Beck Small Particles, Big Hopes: Absorption Enhancement in Silicon using Metallic Nanoparticles

Centre for Super Earth-saving Science

Regular Superhero Solar Energy Superheros

Rubbish absorption above 1000nm Absorption Spectra of Silicon % Absorption Wavelength (nm)

Texturing to trap light in bulk silicon cells light SEM image of textured silicon taken by Luke Johnson

Localised Surface Plasmons in Metal Nanoparticles -e e E-field Incident Light Time t Time t + /2c

Interface effects Incident light Induced surface plasmon Light coupled into silicon in trapped modes Silver Nanoparticle Dielectric layer

1) Silicon wafer, thin and shiny 2) Dielectric film deposition ~30nm Oxidation for SiO2 APCVD TiO2 Sample Fabrication: 3) Silver film evaporation ~10nm 4) Low temperature anneal ~260 degree C Nanoparticles !

Resonance peaks Smallest particles Biggest particles

Optical measurements Particles on front Particles on rear SiO2 CoatingTiO2 Coating Light source

Absorption Spectra for Particles on Silicon

16 fold increase in light absorption for particles on TiO2 at 1150nm 5.6 times more absorption of light at 1150nm for particles on the rear of a silicon-SiO2 sample

Particles on TiO2Particles on SiO2 SEM Images

My supervisors Klaus Weber and Kylie Catchpole, currently at the Institute of Atomic and Molecular Physics in the Netherlands. Luke Johnson for the TiO2 deposition and the nice SEM image and everyone who has helped me out in the labs.