Microstructure and photoluminescence study of vanadium-doped ZnO films

Abstract

Zn1−xVxO films (x = 0, 1.3, 1.9, 2.6, 3.5, 4.3 and 6.2 at%) were prepared on glass substrates via the direct current reactive magnetron co-sputtering method. The microstructure, band gap, photoluminescence and Raman scattering of these films have been systematically investigated. The structural and chemical state characterizations indicate that the crystallinity of Zn1−xVxO films (x ⩽ 2.6 at%) can be improved by V incorporation into the ZnO wurtzite lattice, but excess V will precipitate as V clusters when x ⩾ 4.3 at%, resulting in the deterioration of crystal quality. The defects in Zn1−xVxO films (x ⩽ 2.6 at%) can be suppressed by V doping, which induces the enhancement of the near band edge (NBE) emission. However, when x ⩾ 4.3 at%, defects adjacent to the V dopant quench the NBE emission. On the other hand, the band gap of the films gradually increases with the increase in V concentration, which is accompanied by the blue shift of the NBE emission.