MOVPE growth and study of ZnO, ZnMgO epilayers and ZnO/ZnMgO MQW structures

Due to large exciton binding energy, ZnO/ZnMgO heterostructures are promising for modern optoelectronic devices in the UV range. We report on the metal-organic vapor phase epitaxy (MOVPE) of ZnO, ZnMgO layers and periodic ZnO/ZnMgO MQW structures at atmospheric hydrogen pressure using diethylzinc (DEZ), bismethyl-cyclopentadienil-magnesium ((MeCp)2Mg) and tertiary-butanol (t-BuOH) as precursors. Wurtzite-type layers and MQW structures were grown below 450°C on Al2O3(0001) substrates. The growth rate is constant in the temperature interval from 170 to 430°, and decreases abruptly above 430° as a result of ZnO decomposition in hydrogen. PL and X-ray measurements confirm a wurtzite structure f ZnMgO films with a Mg content of up to 35 at%. The as-grown films show good optical quality and near band edge emission in the photoluminescence (PL) and cathodoluminescence (CL). Periodic ZnO/ZnMgO MQW structures with strong ZnO QWs emission were grown at room temperature.