有機金属気相エピタキシャル法によるユウロピウム添加窒化ガリウムの成長温度依存性

概要

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We investigated the growth temperature dependence of luminescence properties in Eu-doped GaN layers grown by organometallic vapor phase epitaxy (OMVPE). The dominant photoluminescence (PL) peak intensity at 621 nm, due to the intra-4f shell transitions of 5D0-7F2 in Eu3+ ions, became the highest when the sample was grown at 1000°C. Above 1000°C, the PL peak intensity decreased because of the lower Eu concentration associated with the surface desorption of Eu ions. On the other hand, although the Eu concentration of the layer grown at 900°C was only half of the layer grown at 1000°C, the pronounced decline in the PL peak intensity was observed with decreasing growth temperature from 1000°C to 900°C, which results from the modification of the local structure around Eu ions. These results indicate that the growth temperature strongly influences the Eu concentration and the local structure around Eu ions. Therefore, an optimized growth temperature exists for strong Eu-related luminescence from Eu-doped GaN layer grown by OMVPE.