Photoluminescence transient study of surface defects in ZnO nanorods grown by chemical bath deposition

E. G. Barbagiovanni; V. Strano; G. Franzò; I. Crupi; S. Mirabella

doi:10.1063/1.4914067

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arXiv · 1502.03674

Photoluminescence transient study of surface defects in ZnO nanorods grown by chemical bath deposition

E. G. Barbagiovanni·V. Strano·G. Franzò·I. Crupi·S. Mirabella

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Abstract

Two deep level defects (2.25 and 2.03 eV) associated with oxygen vacancies (V$_o$) were identified in ZnO nanorods (NRs) grown by low cost chemical bath deposition. A transient behaviour in the photoluminescence (PL) intensity of the two V$_o$ states was found to be sensitive to the ambient environment and to NR post-growth treatment. The largest transient was found in samples dried on a hot plate with a PL intensity decay time, in air only, of 23 and 80 s for the 2.25 and 2.03 eV peaks, respectively. Resistance measurements under UV exposure exhibited a transient behaviour in full agreement with the PL transient indicating a clear role of atmospheric O$_2$ on the surface defect states. A model for surface defect transient behaviour due to band bending with respect to the Fermi level is proposed. The results have implications for a variety of sensing and photovoltaic applications of ZnO NRs.

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E. G. Barbagiovanni, V. Strano, G. Franzò, I. Crupi, S. Mirabella. 2015-02-12. Photoluminescence transient study of surface defects in ZnO nanorods grown by chemical bath deposition. https://doi.org/10.1063/1.4914067

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