Optical activity and defect/dopant evolution in ZnO implanted with Er

• The effects of annealing on the optical properties and defect/dopant evolution in wurtzite (0001) ZnO single crystals implanted with Er ions are studied using a combination of Rutherford backscattering/channeling spectrometry and photoluminescence measurements. The results suggest a lattice recovery behavior dependent on ion dose and involving formation/evolution of an anomalous multipeak defect distribution, thermal stability of optically active Er complexes, and Er outdiffusion. An intermediate defect band occurring between the surface and ion-induced defects in the bulk is stable up to 900 degrees C and has a photoluminescence signature around 420 nm well corresponding to Zn interstitials. The optical activity of the Er atoms reaches a maximum after annealing at 700 degrees C but is not directly associated to the ideal Zn site configuration, since the Er substitutional fraction is maximal already in the as-implanted state. In its turn, annealing at temperatures above 700 degrees C leads to dissociation of the optically active Er complexes with subsequent outdiffusion of Er accompanied by the efficient lattice recovery.

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NATURVETENSKAP  -- Fysik -- Den kondenserade materiens fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Condensed Matter Physics (hsv//eng)

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