Effects of Aluminium Doping on Kesterite Cu2ZnSnS4 Thin-Films

Nazligül A. S., Wang M., Choy K. L.

MRS 2019 Fall, Massachusetts, United States Of America, 1 - 06 December 2019, pp.1907

  • Publication Type: Conference Paper / Summary Text
  • City: Massachusetts
  • Country: United States Of America
  • Page Numbers: pp.1907
  • Yıldız Technical University Affiliated: Yes


In recent years Cu-based chalcogenide Cu2ZnSnS4 (CZTS) has attracted a lot of attention as an earth-abudant alternative for CIGS solar cells. To date, the research in this field has been focused on solar cell applications. However, the efficiency of CZTS solar cells has not experienced a real improvement in the past five years. Therefore, research is beginning to explore new applications for this material such as sensors, water-splitting and charge-extraction layers. In this project, aluminium doping has been introduced to CZTS thin-films for the first time. CZTS films were deposited in atmospheric conditions via a low-cost and environmentally friendly solution-based method. The effects of up to 3 % Al doping in a range of different annealing temperatures from 350 °C to 550 °C without any sulfurization/selenization were examined. Our results show that Al has no significant effect for the samples heat-treated at 350 °C. On the other hand, we observed successful doping for the samples heat-treated above 450 °C. Our EDS, XRD and Raman results suggest that Al is replacing Sn sites in these samples. The Al doping caused a drop in resistivity while increasing the charge-carrier concentration, bandgap and grain sizes. The biggest reduction in resistivity was observed for 2% doped and heat-treated at 450 °C samples. In these samples the resistivity reduced from 13.34 Ω.cm to 0.42 Ω.cm while charge-carrier concentration increased from 7.85×1017 to 1.74×1020 cm-3. Such improvement in charge-carrier concentration is promising for using Al-doped CZTS thin-films as hole transport layers in Perovskite solar cells, while an increase in the bandgap is advantageous for water-splitting applications.