Effects of the d-donor level of vanadium on the properties of Zn1−xVxO films

We report the effect of d-levels of vanadium atoms on the electronic band structure of ZnO. Polycrystalline layers of Zn1−xVxO with 0 ≤ x ≤ 0.08 were synthesized using magnetron sputtering technique. Electrical measurements show that electron concentration increases with vanadium up to x = 0.04 and...

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Veröffentlicht in:Applied physics letters 2015-05, Vol.106 (18)
Hauptverfasser: García-Hemme, E., Yu, K. M., Wahnon, P., González-Díaz, G., Walukiewicz, W.
Format: Artikel
Sprache:eng
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Zusammenfassung:We report the effect of d-levels of vanadium atoms on the electronic band structure of ZnO. Polycrystalline layers of Zn1−xVxO with 0 ≤ x ≤ 0.08 were synthesized using magnetron sputtering technique. Electrical measurements show that electron concentration increases with vanadium up to x = 0.04 and then decreases and films become insulating for x > 0.06. Optical characterization reveals that the absorption edge shifts to higher energy, while the photoluminescence (PL) peak shows a shift to lower energy with increasing vanadium content. This unusual optical behavior can be explained by an anticrossing interaction between the vanadium d-levels and the conduction band (CB) of ZnO. The interaction results in an upward shift of unoccupied CB (E+) and the downward shift of the fully occupied E− band derived from the vanadium d-levels. The composition dependence of optical absorption edge (E+) and PL peak (E−) can be fitted using the Band Anticrossing model with the vanadium d-level located at 0.13 eV below CB of ZnO and a coupling constant of 0.65 eV.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.4919791