P-type conductivity in Sn-doped Sb2Se3

Theodore D.C. Hobson, Huw Shiel, Christopher N. Savory, Jack E.N. Swallow, Leanne A.H. Jones, Thomas J. Featherstone, Matthew J. Smiles, Pardeep K. Thakur, Tien Lin Lee, Bhaskar Das, Chris Leighton, Guillaume Zoppi, Vin R. Dhanak, David O. Scanlon, Tim D. Veal, Ken Durose, Jonathan D. Major

Research output: Contribution to journalArticlepeer-review

Abstract

Antimony selenide (Sb2Se3) is a promising absorber material for thin-film photovoltaics. However, certain areas of fundamental understanding of this material remain incomplete and this presents a barrier to further efficiency gains. In particular, recent studies have highlighted the role of majority carrier type and extrinsic doping in drastically changing the performance of high efficiency devices (Hobson et al 2020 Chem. Mater. 32 2621-30). Herein, Sn-doped Sb2Se3 bulk crystals are shown to exhibit p-type conductivity using Hall effect and hot-probe measurements. The measured conductivities are higher than those achieved through native defects alone, but with a carrier density (up to 7.4 × 1014 cm-3) several orders of magnitude smaller than the quantity of Sn included in the source material. Additionally, a combination of ultraviolet, X-ray and hard X-ray photoemission spectroscopies are employed to obtain a non-destructive depth profile of the valence band maximum, confirming p-type conductivity and indicating a majority carrier type inversion layer at the surface. Finally, these results are supported by density functional theory calculations of the defect formation energies in Sn-doped Sb2Se3, showing a possible limit on the carrier concentration achievable with Sn as a dopant. This study sheds light on the effectiveness of Sn as a p-type dopant in Sb2Se3 and highlights avenues for further optimisation of doped Sb2Se3 for solar energy devices.

Original languageEnglish (US)
Article number045006
JournalJPhys Energy
Volume4
Issue number4
DOIs
StatePublished - Oct 2022

Bibliographical note

Funding Information:
The Engineering and Physical Sciences Research Council (EPSRC) is acknowledged for funding of H S (Grant No. EP/N509693/1), J E N S, T J F, and M J S (Grant No. EP/L01551X/1), G Z (Grant No. EP/R021503/1) T D C H and K D (Grant No. EP/T006188/1) and V R D and T D V (Grant No. EP/N015800/1). Work at the University of Minnesota was supported by the US DOE through the Center for Quantum Materials under DE-SC0016371, Paul Warren of NSG Group is thanked for discussions and for funding of H S. C N S is grateful to the Department of Chemistry at UCL and the Ramsay Memorial Fellowship Trust for the funding of a Ramsay fellowship. The use of the UCL Myriad and Kathleen High Performance Computing Facilities (Myriad@UCL and Kathleen@UCL) are acknowledged in the production of this work. Computational work was also performed on the ARCHER and ARCHER2 UK National Supercomputing Services, via our membership of the UK’s HEC Materials Chemistry Consortium, funded by EPSRC (EP/L000202, EP/R029431). We also thank Vipul Chaturvedi from University of Minnesota for deposition of Au contacts. Diamond Light Source is acknowledged for I09 beam time under proposal SI23160-1.

Publisher Copyright:
© 2022 The Author(s). Published by IOP Publishing Ltd.

Keywords

  • chalcogenides
  • crystals
  • doping
  • inversion layer
  • photovoltaics
  • SbSe
  • X-ray photoemission

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