Effect of growth temperature on Eu incorporation in GaN powders

Gallium nitride powders: Mechanism of ammonothermal synthesis, ball-mill assisted rare earth doping and uniform electrophoretic deposition

“…This is in agreement with the observation made by Shi et al [26] that both below and above a certain temperature range, RE:GaN crystals grown by ammonothermal methods are of poor quality. In our experience, the ammonothermal growth of optically active Er:GaN has been significantly more difficult than that of Eu:GaN; hence, we adopted the ball-milling method to achieve Er doping.…”

“…We know that at the synthesis temperature, about $ 0.5 at% of Eu is incorporated into the GaN matrix [26]. The enthalpy of vaporization of Eu is known to be 177.9 72.5 kJ mol À 1 , and its vapor pressure at 822 1C is known to be 144 Pa [29,30].…”

“…This alloy is heated in a quartz tube reactor in an argon atmosphere to a temperature of 920 K. This atmosphere is replaced with ammonia as heating is continued beyond 920 K. The system is held at a constant reaction temperature of 1223 K for 5 h, while maintaining a steady partial pressure of ammonia in the reaction chamber. When Ga-Eu-Bi alloy (95.75, 1.25 and 3 at%) is used as the starting material, a high purity Eu:GaN powder with approximately 0.5 at% Eu doping is obtained [26].…”

Purification and mechanical nanosizing of Eu-doped GaN

“…It is reasonable to expect that the visual appearance of Eu:GaN be similar to that of pure GaN because of the relatively dilute concentration of Eu atoms ($0.5 at%) [6]. We demonstrate a chemical process for Eu:GaN particles, which removes the dark particles that contribute to this darker visual appearance of the material and improves the photoluminescence (PL) of these particles by 300% compared to the powder previously reported [6]. The visual clarity approaches that of pure GaN (Fig.…”

Optical and structural properties of Eu-diffused and doped ZnO nanowires

“…Most of the work has focused on incorporation of rare earth ions into GaN films using either in situ doping or direct ion implantation [1][2][3][4][5][6][7][8][9][10][11]. Eu is an attractive dopant for red emission between 540 and 665 nm and the Eu-related luminescence lines are found to be a strong function of the structural quality and thermal cycling in the case of GaN [12,13]. The strongest emission is usually from the 5 D O -7 F 2 transition of the Eu 3+ ion at around 620 nm.…”