n-type CdTe:In for photovoltaics: in situ doping, type verification and compensation effects

Hobson, Theodore DC, Thomas, Luke, Phillips, Laurie J, Jones, Leanne AH, Smiles, Matthew J, Don, Christopher H, Thakur, Pardeep K, Shiel, Huw, Campbell, Stephen, Barrioz, Vincent
et al (show 4 more authors) (2023) n-type CdTe:In for photovoltaics: in situ doping, type verification and compensation effects. Journal of Physics: Energy, 5 (4). 045012-045012.

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<jats:title>Abstract</jats:title> <jats:p>We explored the <jats:italic>in-situ</jats:italic> doping of cadmium telluride thin films with indium to produce n-type absorbers as an alternative to the near-universal choice of p-type for photovoltaic devices. The films were grown by close space sublimation from melt-synthesised feedstock. Transfer of the indium during film growth was limited to 0.0014%–0.014%—unless reducing conditions were used which yielded 14%–28% efficient transport. While chunks of bulk feedstock were verified as n-type by the hot probe method, carrier type of thin film material was only able to be verified by using hard x-ray photoelectron spectroscopy to determine the Fermi level position within the band gap. The assignment of n-type conductivity was consistent with the rectification behaviour of a p-InP/CdTe:In junction. However, chloride treatment had the effect of compensating n-CdTe:In to near-intrinsic levels. Without chloride, the highest dopant activation was 20% of the chemical concentration of indium, this being for a film having a carrier concentration of <jats:italic>n</jats:italic> = 2 × 10<jats:sup>15</jats:sup> cm<jats:sup>−3</jats:sup>. However, the activation was often much lower, and compensation due to over-doping with indium and native defects (stoichiometry) are discussed. Results from preliminary bifacial devices comprising Au/P3HT/ZnTe/CdTe:In/CdS/FTO/glass are presented.</jats:p>

Item Type: Article
Uncontrolled Keywords: CdTe, photovoltaics, n-type, in-situ doping, photoemission
Divisions: Faculty of Science and Engineering > School of Physical Sciences
Depositing User: Symplectic Admin
Date Deposited: 02 Oct 2023 08:15
Last Modified: 25 Oct 2023 11:05
DOI: 10.1088/2515-7655/acfbf8
Open Access URL: https://iopscience.iop.org/article/10.1088/2515-76...
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URI: https://livrepository.liverpool.ac.uk/id/eprint/3173247