Tunable Fluorescence Properties Due to Carbon Incorporation in Zinc Oxide Nanowires

Abstract

AbstractIt is shown experimentally that carbon incorporation into zinc oxide (ZnO) nanowires (NWs) plays a crucial role in determining the NWs' fluorescence and photoluminescence properties. Through intentional adjustment of chemical vapor deposition growth parameters to allow for carbon incorporation, the ZnO NWs' fluorescence under ultraviolet excitation can be varied controllably from green to orange‐red. X‐ray photoelectron spectroscopy, X‐ray absorption spectroscopy, and transmission electron microscopy correlate carbon incorporation to a systematic shifting of ZnO NWs' fluorescence toward higher wavelengths. This is consistent with a previous theoretical prediction of orange‐red fluorescence arising from a carbon‐related defect within ZnO. In the present work, further computational results from simulation of high carbon content within the ZnO lattice yield additional carbon‐related defect species as possible origins of orange‐red fluorescence. Furthermore, the extent of simulated band gap energies can help explain the broad visible fluorescence spectrum from carbon incorporated ZnO. Additional experiments involving plasma etching and oxygen annealing agree with the inferences of carbon‐related defects as a source of variable visible‐light emissions.