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Tellurium vacancy in cadmium telluride revisited: Size effects in the electronic properties (Phys. Status Solidi B 12/2015)
Author(s) -
MenéndezProupin E.,
Orellana W.
Publication year - 2015
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201570375
Subject(s) - supercell , vacancy defect , cadmium telluride photovoltaics , atom (system on chip) , materials science , tellurium , density functional theory , condensed matter physics , conduction band , crystallographic defect , optoelectronics , electron , chemistry , physics , computational chemistry , quantum mechanics , computer science , metallurgy , embedded system , thunderstorm , meteorology
Cadmium telluride (CdTe) is currently a key material for the second‐generation thin‐film solar cells with efficiency reaching up to 21.5%. This efficiency improvement is mainly achieved by suppressing recombination centers. Therefore, the identification of recombination centers, typically induced by native defects like vacancies and antisites is quite important. The state‐of‐the‐art methodology to identify such defects is based on the density functional theory using quasi‐particle corrections and large unit cells, commonly including 64 atoms. Menéndez‐Proupin and Orellana (pp. 2649–2656 ) have revisited the tellurium vacancy, which is pointed out as a dominant donor, having a strong influence on the CdTe electric and thermodynamic properties. They showed that the 64‐atom supercell introduces unphysical features, notably a dramatic alteration of the CdTe conduction band, making uncertain to apply simple quasi‐particle corrections. Indeed, the band‐filling error associated to the k‐point sampling can drive the system to unreal distorted configurations. Reliable results for the structural and electronic properties can be obtained with a 512‐atom supercell with the Γ‐point sampling. Alternatively, a 216‐atom supercell can be used but with careful analysis of the band‐filling error.