Silicon quantum dot based solar cells: addressing the issues of doping, voltage and current transport

Gavin Conibeer*, Martin A. Green, Dirk König, Ivan Perez-Wurfl, Shujuan Huang, Xiaojing Hao, Dawei Di, Lei Shi, Santosh Shrestha, Binesh Puthen-Veetil, Yong So, Bo Zhang, Zhenyu Wan

*Corresponding author for this work

Research output: Contribution to journalConference paperpeer-review

68 Citations (Scopus)


Silicon quantum dot (Si QD) solar cells offer the potential to tune the effective band gap through quantum confinement and hence allow fabrication of optimised tandem devices in one growth run in a thin film process. Previous work in our group has shown how such cells can be fabricated by sputtering of thin layers of silicon rich oxide sandwiched between a stoichiometric oxide that on annealing crystallise to form Si QDs of uniform and controllable size. Doping multilayers with P and B allows formation of a rectifying junction with an effective band gap of 1.8 eV, which can give an open circuit voltage (VOC) of almost 500 mV. However, the doping behaviour of P and B in these QD materials is not well understood. In addition P and B have big but opposite effects on QD crystallisation, with P(B) forming larger (smaller) QDs than for undoped material. Two possible models for the doping mechanisms in these materials are explored: one relying on doping of a sub‐oxide region around the Si QDs and the other based on the differing nucleation effects of P and B. In addition initial results on hetero‐interfaces in the QD superstructure are assessed as a means to improve vertical current transport, and the effects of hydrogenation on improving VOC by passivating defects. Routes to incorporating these explanations for doping and other structural improvements are discussed as means of optimising the performance of these Si QD cells.

Original languageEnglish
Pages (from-to)813-824
Number of pages12
JournalProgress in Photovoltaics: Research and Applications
Issue number7
Publication statusPublished - Nov 2011
Externally publishedYes
Event25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion - Valencia, Spain
Duration: 6 Sept 201010 Sept 2010


  • band gap engineering
  • modulation doping
  • nucleation
  • tandem
  • quantum dots


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