Rapid Recombination by Cadmium Vacancies in CdTe

Abstract

CdTe is a key thin-film photovoltaic technology. Non-radiative electron-hole recombination reduces the solar conversion efficiency from an ideal value of 32% to a current champion performance of 22%. The cadmium vacancy (V_Cd) is a prominent acceptor species in p-type CdTe; however, debate continues regarding its structural and electronic behavior. Using ab initio defect techniques, we calculate a negative-U double-acceptor level for V_Cd, while reproducing the V_Cd^-1 hole-polaron, reconciling theoretical predictions with experimental observations. We find the cadmium vacancy facilitates rapid charge-carrier recombination, reducing maximum power-conversion efficiency by over 5% for untreated CdTe -- a consequence of tellurium dimerization, metastable structural arrangements, and anharmonic potential energy surfaces for carrier capture.

References in corpus (9)

• First-principles theory of nonradiative carrier capture via multiphonon emission
• Perovskite-Inspired Materials for Photovoltaics -- From Design to Devices
• Upper limit to the photovoltaic efficiency of imperfect crystals
• Bandgap Lowering in Mixed Alloys of Cs2Ag(SbxBi1-x)Br6 Double Perovskite Thin Films
• Defect identification based on first-principles calculations for deep level transient spectroscopy
• What Causes High Resistivity in CdTe
• Anharmonic Lattice Relaxation during Non-radiative Carrier Capture
• Characterisation of negative-U defects in semiconductors
• Flat (001) surfaces of II-VI semiconductors: A lattice gas model

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