ZnO and ZnO:Mn crystals obtained with the chemical vapour transport method

摘要

Successful growth of the ZnO and ZnO:Mn crystals by the CVT method and their characterisation are reported. The source material was synthesized at 650℃ from oxygen and zinc vapours and subsequently -baked (as a powder) to achieve stoichiometry. Crystal growth (at ～1100℃, with the rate ～1-2 mm/day) proceeded in graphite-covered quartz ampoules containing pure (6N) hydrogen or nitrogen or chlorine and a little of water vapour and carbon. The crystals, both as-grown and annealed in pure oxygen, were characterised by the measurements of: transmission spectra in energy gap and far infrared regions, photolumi-nescence and reflectivity spectra, electrical transport properties and EDXRF - the energy dispersive X-ray fluorescence (for Mn content determination). In the surface region - the impurities and the Mn content were studied by the secondary ion mass spectroscopy (SIMS). Manganese and native defects (V_O) were investigated by electron paramagnetic resonance (EPR) and Raman spectroscopy. Results of the measurements are presented and discussed.