Nanoscale charge transport and local surface potential distribution to probe defect passivation in Ag doped Cu2ZnSnS4 absorbing layer

Kulwinder Kaur, Kanika Arora, Bahrami Behzad, Qiquan Qiao, Mukesh Kumar

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

The performance of earth abundant Cu2ZnSnS4 (CZTS) material is limited by high deficit of open circuit voltage (VOC) which is mainly due to the easy formation of CuZn antisite defects. Suppression of CuZn defects is thus inevitably required for further developments in CZTS based solar cells. We studied systematic increase of Ag doping in CZTS thin film and investigated the nanoscale electrical properties using Kelvin probe force microscopy and current sensing atomic force microscopy (CAFM) to probe CuZn defects. Crystallographic analysis indicated the successful partial substitution of Cu+ ions by large size Ag+ ions. The considerable decrease in grain boundary potential from 66.50 5.44 mV to 13.50 2.61 mV with Ag doping, suggesting the substantial decrease in CuZn defects. Consequently, CAFM measurement confirms the remarkable increment in minority carrier current with Ag doping and their local mobility in CZTS layer. Finally, the lower persistent photoconductivity and fast decay response of photogenerated carriers for Ag doped CZTS photodetector further validate our results. This study provides a fresh approach of controlling deleterious CuZn defects in CZTS by tuning Ag content that may guide researchers to develop next generation high-performance CZTS based solar cells.

Original languageEnglish (US)
Article number065706
JournalNanotechnology
Volume30
Issue number6
DOIs
StatePublished - Feb 8 2019
Externally publishedYes

Keywords

  • Ag doped CZTS
  • CZTS solar cells
  • defects
  • nanoscale surface potential and current
  • photodetector

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering
  • Electrical and Electronic Engineering

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