Post growing annealing effect on the optical, electrical and structural properties of CdSe nanocrystals embedded in silica thin films

In this work post-growth annealing effect on CdSe/SiO2 thin films grown by rf-magnetron co-sputtering technique was investigated. Annealed samples were characterised by Raman scattering, grazing incidence X-ray diffraction and room temperature photoluminescence. The nanocrystals (NCs) size changed from 15 to 5 nm by varying the annealing temperature from 550 to 400 degrees C Evaporation of Se at high temperatures was invoked to explain this phenomenon. Fowler-Nordheim tunnelling mechanism was found to be responsible for carrier transport for samples with bigger CdSe NCs sizes, and which showed better photovoltaic properties.Fundação para a Ciência e a Tecnologia (FCT) "Programa Operacional Ciência e Inovação 2010-POCI 2010" co-financed by FEDER (Fundo Comunitário Europeu), Project POCTI/FIS/56930/2004, SFRH/BPD/26532/2006FP6 of the European Commission, project SEMINANO (subcontracts under contract NMP4-CT--2004-505285)