Structural and Optical Properties of Fe-Doped ZnO Nanorods

Fe-doped zinc oxide nanorods (ZnO NRs) were synthesized by ex-situ doping using spray pyrolysis technique. In this work, the undoped ZnO NRs were pre-synthesized via chemical vapor deposition using Zn powder and oxygen gas at 650 degrees C. The average length and diameter of the ZnO NRs are 4.1 +/- 1.1 mu m and 553.1 +/- 89.6 nm, respectively. The average aspect ratio and areal density of ZnO NRs is 8.2 +/- 2.9 and 6.2 +/- 1.1 NRs/um(2), respectively. Subsequently, these undoped ZnO NRs were kept in the horizontal tube furnace, whereas the dopant solution (FeCl3) of 0.05 M concentration was kept in the aerosol generator, which was located outside of the furnace. The Fe aerosol was flowed into the reactor when substrate temperature reached 650 degrees C to achieve ex-situ doping. At this temperature, some of the Fe atoms were driven into the NRs, forming Fe-doped ZnO NRs particularly at their outer layer. The presence of Fe 2p1/2 and Fe 2p(1/2) peaks at 722.3 eV and 705.7 eV in XPS analysis indicates that Fe atoms were in the local structure of FeO. The Fe-doped ZnO NRs have poor crystal quality attributed to the low/I(UV)vavis ratio in room temperature PL analysis.