Department Physics/Stephenson Inst for Renewable Energy, University Liverpool , Liverpool L69 7ZF, United Kingdom
Luke Thomas
Department Physics/Stephenson Inst for Renewable Energy, University Liverpool , Liverpool L69 7ZF, United Kingdom
Laurie J Phillips
Department Physics/Stephenson Inst for Renewable Energy, University Liverpool , Liverpool L69 7ZF, United Kingdom
Leanne A H Jones
Department Physics/Stephenson Inst for Renewable Energy, University Liverpool , Liverpool L69 7ZF, United Kingdom; Now at: Department of Materials, University of Oxford , Oxford OX1 3PH, United Kingdom.
Department Physics/Stephenson Inst for Renewable Energy, University Liverpool , Liverpool L69 7ZF, United Kingdom; Now at: Department of Materials, Imperial College London , Prince Consort Road, London SW7 2BP, United Kingdom.
Stephen Campbell
Department of Mathematics, Physics and Electrical Engineering, University Northumbria , Newcastle-upon-Tyne NE1 8ST, United Kingdom
Vincent Barrioz
Department of Mathematics, Physics and Electrical Engineering, University Northumbria , Newcastle-upon-Tyne NE1 8ST, United Kingdom
Vin Dhanak
Department Physics/Stephenson Inst for Renewable Energy, University Liverpool , Liverpool L69 7ZF, United Kingdom
Tim Veal
Department Physics/Stephenson Inst for Renewable Energy, University Liverpool , Liverpool L69 7ZF, United Kingdom
Jonathan D Major
Department Physics/Stephenson Inst for Renewable Energy, University Liverpool , Liverpool L69 7ZF, United Kingdom
We explored the in-situ 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 n = 2 × 10 ^15 cm ^−3 . 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.