Electron spin resonance study of photoluminescent material GaAs:Er,O-Er concentration effect

• Published in: Journal of applied physics 2011-03, Vol.109 (5), p.053910-053910-5
• Main Authors: Fujisawa, Masashi, Asakura, Atsushi, Elmasry, Fatma, Okubo, Susumu, Ohta, Hitoshi, Fujiwara, Yasufumi
• Format: Article
• Language: English
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.3556453

Although the photoluminescent material GaAs:Er,O has attracted much attention, the mechanism underlying its luminescence is unclear. To elucidate this mechanism, we have performed X-band electron spin resonance (ESR) measurements for different Er concentration samples. Several anisotropic ESR signals (A, B, and C) were observed, which is consistent with the previous reports. When the Er concentration is increased, the angular dependence of the resonance field is not affected, but the linewidth increases. From the Er concentration dependence of linewidth and the lineshape analysis, the dominant interaction between spins is not the magnetic dipole interaction but the exchange interaction. From the temperature dependence of integrated intensity, the exchange interaction between the nearest Er ions is antiferromagnetic, and this system has a singletlike ground state. We conclude that the Er-2O center is not distributed homogeneously in GaAs. A possible model is that the luminescent Er-related center consists of two Er atoms and that the luminescent B center seems to form pairs with the C center.