Formation of luminescent centers in GaN powders by the two-stage vapor phase synthesis and their phosphor application

点击翻译按钮获取中文摘要

1.The characterization of undoped GaN powders on the constituent of gases, GaCl,NH_3 and H_2, and their partial pressures at the stage of particle growth was carried out systematically. Based on these results, the dramatic improvement in the luminescent property of the samples has been achieved.2.The synthesis of GaN:Zn powders by the two-stage vapor phase method, in which a ZnS powder was used as a source for the stage of particle growth. The supply rate of ZnS was controlled by choice of carrier gas (N_2 or HCl) and their flow rate, which enabled the extensive control of Zn concentration between 1×10^<19>〜8×10^<20> cm^<-3>. It was found that S of almost the same concentration as Zn was also incorporated in the samples.3.The synthesized GaN:Zn powder showed blue photomminescence and cathodeluminescence. The spectra consisted of a broad emission band located around 450 nm. The emission was characterized systematically on the Zn concentration.4.It was found that the luminescence from the GaN:Zn powder is dependent strongly on the partial pressure of NH_3 at the stage of particle growth. The emission intensity increased with increasing the partial pressure in the region up to 0.78 atm.5.The dramatic improvement in the luminescence and crystalline properties has been achieved by using Zn metal as a source instead of ZnS, which suggests that the incorporation of S has a negative effect on the quality of samples.