Ishikawa Ryo, Lupini Andrew R, Oba Fumiyasu, Findlay Scott D, Shibata Naoya, Taniguchi Takashi, Watanabe Kenji, Hayashi Hiroyuki, Sakai Toshifumi, Tanaka Isao, Ikuhara Yuichi, Pennycook Stephen J
Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
1] Department of Materials Science and Engineering, Kyoto University, Sakyo, Kyoto 606-8501, Japan [2] Materials Research Center for Element Strategy, Tokyo Institute of Technology, Yokohama 226-8503, Japan.
Sci Rep. 2014 Jan 21;4:3778. doi: 10.1038/srep03778.
Rare-earth doped wurtzite-type aluminum nitride (w-AlN) has great potential for high-efficiency electroluminescent applications over a wide wavelength range. However, because of their large atomic size, it has been difficult to stably dope individual rare-earth atoms into the w-AlN host lattice. Here we use a reactive flux method under high pressure and high temperature to obtain cerium (Ce) doped w-AlN single crystals with pink-colored luminescence. In order to elucidate the atomic structure of the luminescent centers, we directly observe individual Ce dopants in w-AlN using annular dark-field scanning transmission electron microscopy. We find that Ce is incorporated as single, isolated atoms inside the w-AlN lattice occupying Al substitutional sites. This new synthesis method represents a new alternative strategy for doping size-mismatched functional atoms into wide band-gap materials.
稀土掺杂的纤锌矿型氮化铝（w-AlN）在宽波长范围内的高效电致发光应用中具有巨大潜力。然而，由于稀土原子尺寸较大，将单个稀土原子稳定地掺杂到w-AlN主晶格中一直很困难。在此，我们采用高温高压下的反应熔剂法获得了具有粉红色发光的铈（Ce）掺杂w-AlN单晶。为了阐明发光中心的原子结构，我们使用环形暗场扫描透射电子显微镜直接观察w-AlN中的单个Ce掺杂剂。我们发现Ce以单个孤立原子的形式掺入w-AlN晶格中，占据Al替代位点。这种新的合成方法为将尺寸不匹配的功能原子掺杂到宽带隙材料中提供了一种新的替代策略。
