Effects of the d-donor level of vanadium on the properties of Zn_(1-x)V_(x)O films
We report the effect of d-levels of vanadium atoms on the electronic band structure of ZnO. Polycrystalline layers of Zn_(1-x)V_(x)O with 0 ≤ x ≤ 0.08 were synthesized using magnetron sputtering technique. Electrical measurements show that electron concentration increases with vanadium up to x = 0.0...
| Authors: | , , , , |
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| Format: | article |
| Publication Date: | 2015 |
| Country: | España |
| Institution: | Universidad Complutense de Madrid (UCM) |
| Repository: | Docta Complutense |
| Language: | English |
| OAI Identifier: | oai:docta.ucm.es:20.500.14352/24080 |
| Online Access: | https://hdl.handle.net/20.500.14352/24080 |
| Access Level: | Open access |
| Keyword: | 537 ZnO thin-films Semiconductor Band Alloys States. Electricidad Electrónica (Física) 2202.03 Electricidad |
| Summary: | We report the effect of d-levels of vanadium atoms on the electronic band structure of ZnO. Polycrystalline layers of Zn_(1-x)V_(x)O 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. |
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