A possible new origin of long absorption tail in Nd-doped yttrium aluminum garnet induced by 15 MeV gold-ion irradiation and heat treatment

Journal Article · Sat May 07 00:00:00 EDT 2016 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4948348· OSTI ID:22596929

Amekura, Hiro ^[1]; Akhmadaliev, Shavkat; Zhou, Shengqiang ^[2]; Chen, Feng ^[3]

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1. National Institute for Materials Science (NIMS), Tsukuba, Ibaraki 305-0003 (Japan)
2. Helmholtz-Zentrum Dresden-Rossendorf, Institute of Ion Beam Physics and Materials Research, D-01328 Dresden (Germany)
3. School of Physics, State Key Laboratory of Crystal Materials and Key Laboratory of Particle Physics and Particle Irradiation (Ministry of Education), Shandong University, Jinan 250100 (China)

When ion irradiation introduces point-defects in semiconductors/insulators, discrete energy levels can be introduced in the bandgap, and then optical transitions whose energies are lower than the bandgap become possible. The electronic transitions between the discrete level and the continuous host band are observed as a continuous tail starting from the fundamental edge. This is the well-known mechanism of the absorption tail close to the band-edge observed in many semiconductors/insulators. In this paper, we propose another mechanism for the absorption tail, which is probably active in Nd-doped yttrium aluminum garnet (Nd:YAG) after ion irradiation and annealing. A Nd:YAG bulk crystal was irradiated with 15 MeV Au{sup 5+} ions to a fluence of 8 × 10{sup 14} ions/cm{sup 2}. The irradiation generates an amorphous layer of ∼3 μm thick with refractive index reduction of Δn = −0.03. Thermal annealing at 1000 °C induces recrystallization to randomly aligned small crystalline grains. Simultaneously, an extraordinarily long absorption tail appeared in the optical spectrum covering from 0.24 to ∼2 μm without fringes. The origin of the tail is discussed based on two models: (i) conventional electronic transitions between defect levels and YAG host band and (ii) enhanced light scattering by randomly aligned small grains.

• OSTI ID: 22596929
• Journal Information: Journal of Applied Physics, Vol. 119, Issue 17; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ABSORPTION
ALUMINIUM
ANNEALING
CRYSTALS
DEFECTS
DOPED MATERIALS
ENERGY LEVELS
GARNETS
GOLD
GOLD IONS
HEAT
IRRADIATION
LIGHT SCATTERING
MEV RANGE 10-100
NEODYMIUM LASERS
POINT DEFECTS
RECRYSTALLIZATION
REFRACTIVE INDEX
SEMICONDUCTOR MATERIALS
YTTRIUM