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Development of group-III- nitride-based nanostruchue-embedded phosphor particles

III族氮化物基纳米结构嵌入荧光粉颗粒的开发

基本信息

批准号：
17360138
负责人：
HARA Kazuhiko
金额：
$ 8.29万
依托单位：
Shizuoka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

项目摘要

In contrast to the conventional powder phosphors consisting of particles with a uniform material composition, GaN-based nanostructure-embedded particles, which consist of GaN quantum dots or quantum wells in the AlN matrix, has been proposed to have higher luminescence efficiencies owing to the carrier confinement effect. As a fundamental technique to fabricate such particles, the following three processes have been demonstrated by using the vapor phase method.(1) The AlN particles were first formed by a reaction of vaporized Al and N_2 gas at temperatures (T_1) from 1100 to 1250℃ in the first reactor. Although the sample prepared at 1100℃ is a mixture of AlN particles and unreacted Al, those prepared at T_1 higher than 1150℃ are a single phase AlN. It was found that the reaction temperature of 1200℃ is favorable from a viewpoint of producing the high quality AlN particles.(2) At the second step, GaN was grown on the AlN core particles by a reaction of GaCl and NH_3 at 1000℃ in the second reactor. It can be seen that the particle diameter was increased from 0.1-0.2 μm for the AlN core. Thus fabricated GaN/AlN bilayer particles showed cathodoluminescence dominated by the band edge emission of GaN, indicating a high crystalline quality of the overgrown GaN.(3) AlN was deposited on the surface of GaN particles by a reaction of AlCl_3 and NH_3 in the downstream part of the second reactor. AlN-coated particle showed photoluminescence (PL) dominated by the band edge emission of GaN. The dependence of AlCl_3 supply rate on the PL property suggests the effects of surface barrier to the excited carriers and passivation to surface defects.

与由具有均匀材料组成的颗粒组成的常规粉末磷光体相比，已提出由AlN基质中的GaN量子点或量子威尔斯组成的GaN基纳米结构嵌入颗粒由于载流子限制效应而具有更高的发光效率。作为制造这种颗粒的基本技术，已经通过使用气相方法证明了以下三个过程。(1)在第一反应器中，在1100 ~ 1250℃温度范围内，Al和N_2气体的气化反应首先生成AlN颗粒。在1100℃下制备的样品为AlN颗粒和未反应Al的混合物，而在高于1150℃的T_1下制备的样品为单相AlN。结果发现，从生产高质量AlN颗粒的观点来看，1200℃的反应温度是有利的。(2)在第二步中，在第二反应器中，通过GaCl和NH_3在1000℃下的反应在AlN核心颗粒上生长GaN。可以看出，对于AlN核，颗粒直径从0.1 μm增加到0.2 μm。由此制造的GaN/AlN双层颗粒显示出由GaN的带边发射主导的阴极发光，表明过度生长的GaN的高结晶质量。(3)在第二反应器的下游部分中，通过AlCl_3和NH_3的反应在GaN颗粒的表面上沉积AlN。AlN包覆颗粒的光致发光（PL）由GaN的带边发射为主。AlCl_3供给速率对发光性能的影响表明，表面势垒对激发载流子的作用和表面缺陷的钝化作用。