Improved Blue‐Emitting AlN:Eu2+ Phosphors by Alloying with GaN. Issue 12 (31st August 2015)

• Record Type: Journal Article
• Authors: Yin, Liang‐Jun; Chen, Guo‐Zhang; Zhou, Zheng‐Yang; Jian, Xian; Xu, Bao; He, Ji‐Hua; Tang, Hui; Luan, Chun‐Hong; Xu, Xin; van Ommen, J. Ruud; (Bert) Hintzen, Hubertus T.
• Is Part Of: Journal of the American Ceramic Society. Volume 98:Issue 12(2015)
• Page Start: 3897
• Page End: 3904
• Publication Date: 2015-08-31
• Subjects: Ceramics -- Periodicals; 620.1405
• DOI: 10.1111/jace.13845
• Languages: English
• ISSNs: 0002-7820

Abstract

Abstract : A method is designed to improve the luminescence of AlN‐based phosphors by tuning the band structure and crystal structure due to alloying with GaN. The pure (Al, Ga)N:Eu phosphors were initially prepared by gas‐phase reaction in an NH3 atmosphere. GaN alloying was used to expand the crystal lattice of AlN due to Ga 3+ substituting for smaller Al 3+ ions, making dissolution of Eu 2+ easier. The dissolution of Ga in the AlN lattice was proven by the result of the Rietveld refinement and the increase in lattice parameters with increasing Ga content. To introduce other energy states mixing with the 5 d states of Eu 2+, Ga doping was also used to tune the band structure of AlN by acting on Eu 2+ ions. The theoretical result was analyzed using the Cambridge Sequential Total Energy Package (CASTEP). According to the calculated total and atom resolved partial density of states, it was observed that the Ga 5 p states contribute a large portion to the corresponding Eu 2+ absorption band in (Al, Ga)N:Eu phosphors. As a consequence, an enhanced emission intensity at 470 nm and a high quantum efficiency for excitation at 330 nm was obtained despite of stronger thermal quenching of the (Al, Ga)N:Eu phosphors compared with AlN:Eu.