Dresden 2009 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 36: ZnO: preparation and characterization II

HL 36.8: Talk

Wednesday, March 25, 2009, 16:00–16:15, POT 51

On Cu diffusion in ZnO — •F. Herklotz, E.V. Lavrov, and J. Weber — Technische Universität Dresden, 01062 Dresden, Germany

Copper in ZnO is of special interest since recent theoretical and experimental studies found ferromagnetic behavior of ZnO:Cu at room temperature. In addition, Cu is a deep acceptor in ZnO and one of the causes of the green emission band.

Experimental studies of Cu diffusion in bulk ZnO single crystals were carried out in the temperature range 1030 to 1180 ^∘C. Concentration profiles of substitutional Cu were determined via IR absorption at 5817 cm⁻¹. Our findings reveal that the diffusion coefficient of Cu is 7.6 × 10⁷ exp(−4.56 eV/k_BT) cm²s⁻¹. This is about a factor of 25 higher than reported in the earlier studies, which probed the total Cu concentration. The discrepancy is explained by the formation of Cu complexes, which occurs at high concentrations. Diffusion mechanisms are discussed.