Growth of ZnO nanowires through thermal oxidation of metallic zinc films on CdTe substrates

► ZnO nanowires grown from thermal Zn oxidation. ► TEM reveals high quality thin nanowires several microns long. ► New phase formation at long oxidation time. ► Good spectroscopic properties measured by Raman, Photo and Cathodoluminsecence spectroscopies. 〈 1 1 2 ¯ 0 〉 wurtzite ZnO nanowires (NWs) have been obtained by oxidizing in air at 500 °C thermally evaporated Zn metal films deposited onto CdTe substrates. The presence of Cd atoms from the substrate on the ZnO seeding layer and NWs seems to affect the growth of the NWs. The effects of the oxidation time on the structural and optical properties of the NWs are described in detail. It is shown that the NWs density decreases and their length increases when increasing the oxidation time. Thicker Zn layers result in thinner and longer ZnO NWs. Very long oxidation times also lead to the formation of a new CdO phase which is related to the partial destruction and quality reduction of the NWs. The possible process for ZnO NW formation on CdTe substrates is discussed.