Intrinsic stoichiometry and oxygen-induced p-type conductivity of pyrite FeS2

Citation Sun, Ruoshi et al. " Intrinsic stoichiometry and oxygen-induced p-type conductivity of pyrite FeS_{2}. " Physical Review B 84 Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. The stoichiometry and ubiquitous observation of p-type conductivity of synthetic pyrite FeS 2 thin films are investigated via first-principles computations of native (vacancies, interstitials, antisites) and extrinsic (O S , O i) point defects. Native defects have high formation energies and are predicted to occur in low concentrations within the Fe-and S-rich limits, showing that pyrite should be intrinsically stoichiometric. Under sufficiently oxidizing conditions, O S becomes the most dominant defect type and induces p-type conductivity. At the experimental oxygen impurity concentration, the hole concentration is predicted to be O(10 19) cm −3 , in agreement with Hall measurements reported in the literature. Therefore, we attribute the unintentional p-type conductivity of pyrite to oxygen impurities and propose that improvements in device performance may be achieved under more reducing conditions.