Thin film growth of Ba(Zn,Fe)2As2 by molecular beam epitaxy

We have grown Ba(Zn1-xFex)(2)As-2 thin films by molecular beam epitaxy. Epitaxial thin films with various Fe contents up to x = 0.16 were obtained by employing fluoride substrates and supplying Zn and As in excess. The film of the parent compound BaZn2As2 showed a metallic behavior in the temperature range of 50-300 K, although semiconducting behavior with a bandgap of 0.23 eV has been reported for a polycrystalline bulk sample. The metallic behavior can be ascribed to a defect layer near the film/substrate interface that was found by a cross-sectional microstructure observation. For the Fe-substituted films, on the other hand, no such defect layer was observed, and the temperature dependence of resistivity showed semiconducting behavior. BaZn2As2 is known as a parent compound of diluted magnetic semiconductors, but the magnetization measurements of the Fe doped films showed no evidence of ferromagnetic order.