title: Silicon quantum dot/crystalline silicon solar cells.
abstract: Silicon (Si) quantum dot (QD) materials have been proposed for 'all-silicon' tandem solar cells. In this study, solar cells consisting of phosphorus-doped Si QDs in a SiO(2) matrix deposited on p-type crystalline Si substrates (c-Si) were fabricated. The Si QDs were formed by alternate deposition of SiO(2) and silicon-rich SiO(x) with magnetron co-sputtering, followed by high-temperature annealing. Current tunnelling through the QD layer was observed from the solar cells with a dot spacing of 2 nm or less. To get the required current densities through the devices, the dot spacing in the SiO(2) matrix had to be 2 nm or less. The open-circuit voltage was found to increase proportionally with reductions in QD size, which may relate to a bandgap widening effect in Si QDs or an improved heterojunction field allowing a greater split of the Fermi levels in the Si substrate. Successful fabrication of (n-type) Si QD/(p-type) c-Si photovoltaic devices is an encouraging step towards the realization of all-silicon tandem solar cells based on Si QD materials.
authors.affiliation: Photovoltaics Centre of Excellence, University of New South Wales, Sydney 2052, Australia.
authors.forename: Eun-Chel
authors.initials: EC
authors.lastname: Cho
authors.forename: Sangwook
authors.initials: S
authors.lastname: Park
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Hao
authors.forename: Dengyuan
authors.initials: D
authors.lastname: Song
authors.forename: Gavin
authors.initials: G
authors.lastname: Conibeer
authors.forename: Sang-Cheol
authors.initials: SC
authors.lastname: Park
authors.forename: Martin A
authors.initials: MA
authors.lastname: Green