Optical detection of electron paramagnetic resonance reveals the $I=7∕2$ EPR spectrum of ${\mathrm{V}}^{2+}$ in the sharp photoluminescence (PL) lines often observed at $\sim 6885{\mathrm{cm}}^{-1}$ in ZnO, which have universally been assumed previously to arise from copper. An alternative model for the origin of the lines is tentatively presented therefore which involves vanadium as a trace impurity rather than copper. An additional $I=7∕2$ spectrum, of unknown origin, is also detected both in these lines and in the stronger visible PL of the material.

• Received 18 November 2004

DOI:https://doi.org/10.1103/PhysRevB.71.115205