Blue luminescence of Au nanoclusters embedded in silica matrix

Journal Article · Wed Dec 22 00:00:00 EST 2004 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.1814939· OSTI ID:20658148

Dhara, S; Chandra, Sharat; Magudapathy, P; Kalavathi, S; Panigrahi, B K; Nair, K G.M.; Sastry, V S; Hsu, C W; Wu, C T; Chen, K H; Chen, L C ^[1]

---

1. Materials Science Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India)

Photoluminescence study using the 325 nm He-Cd excitation is reported for the Au nanoclusters embedded in SiO{sub 2} matrix. Au clusters are grown by ion beam mixing with 100 KeV Ar{sup +} irradiation on Au [40 nm]/SiO{sub 2} at various fluences and subsequent annealing at high temperature. The blue bands above {approx}3 eV match closely with reported values for colloidal Au nanoclusters and supported Au nanoislands. Radiative recombination of sp electrons above Fermi level to occupied d-band holes are assigned for observed luminescence peaks. Peaks at 3.1 and 3.4 eV are correlated to energy gaps at the X- and L-symmetry points, respectively, with possible involvement of relaxation mechanism. The blueshift of peak positions at 3.4 eV with decreasing cluster size is reported to be due to the compressive strain in small clusters. A first principle calculation based on density functional theory using the full potential linear augmented plane wave plus local orbitals formalism with generalized gradient approximation for the exchange correlation energy is used to estimate the band gaps at the X- and L-symmetry points by calculating the band structures and joint density of states for different strain values in order to explain the blueshift of {approx}0.1 eV with decreasing cluster size around L-symmetry point.

• OSTI ID: 20658148
• Journal Information: Journal of Chemical Physics, Vol. 121, Issue 24; Other Information: DOI: 10.1063/1.1814939; (c) 2004 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANNEALING
ARGON IONS
ATOMIC CLUSTERS
DENSITY FUNCTIONAL METHOD
ELECTRON CORRELATION
ELECTRONS
ENERGY GAP
EV RANGE 01-10
FERMI LEVEL
GOLD
ION BEAMS
KEV RANGE
MILLI EV RANGE
NANOSTRUCTURES
PHOTOLUMINESCENCE
SILICON OXIDES
SPECTRAL SHIFT
STRAINS
SYMMETRY