Structural and optical characterization of hybrid ZnO/polymer core-shell nanowires fabricated by oxidative chemical vapour deposition

Polycrystalline (pc) n‐doped ZnO layers and n‐doped ZnO nanowires are coated with the p‐doped organic poly‐mers polypyrrole and poly(3,4‐ethylenedioxythiophene) (PEDOT) by oxidative chemical vapour deposition. The structural characterization of the polypyrrole‐coated pc‐ZnO layer shows that the thickness and homogeneity of the polymer shell depends on the amount of the oxidizing agent FeCl3. Electrical measurements of the formed pn‐junction prepared with 0.1 g and 0.3 g FeCl3, show ideality factors of η = 1.7 and η = 4, representing the quality of the formed diode (ideal case η = 1), which is decreasing with increasing amount of oxidizing agent. Structural studies of the hybrid core‐shell nanowires reveal that a thin and homogeneous coating of the nanowires is achieved by using 0.1 g FeCl3. Energy dispersive X‐ray measurements confirm that chlorine is incorporated into the polymer shell. Optical characterization of the hybrid structures via photoluminescence measurements show a broadening of the exciton lines of the ZnO nanowires after polymer coating (especially for PEDOT) which is attributed to etching processes of the wire surface occurring during the application of FeCl3, whereas, the general optical properties of ZnO are not affected. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)