Si quantum dots for solar cell fabrication

Thin film stacks, made of Si-rich SiO alternated with SiO2 layers, have been deposited by reactive RF sputtering starting from Si and SiO2 targets, respectively. Crystalline quantum dots (QDs) have been nucleated by Si precipitation from the Si-rich SiO phase using high temperature annealing. PL measurements evidenced a blueshift of the emission peak which has been attributed to a reduction of the Si QD size. Electrical resistivity measurements showed a semiconducting-like behaviour. QD size affect the resistivity values and the activation energies. We have tentatively interpreted the electrical behaviour of this quantum structure by using a Meyer-Neldel Rule conventionally used to explain the electrical properties of nanoporous silicon.