Low-temperature UV photoluminescence of ion beam synthesized Si nanoclusters embedded in Si

• Published in: Advances in natural sciences. Nanoscience and nanotechnology Vol. 3; no. 2; pp. 25002 - 1-4
• Main Authors: Sahu, G, Lenka, H P, Mahapatra, D P, Rout, B, Das, M P
• Format: Journal Article
• Language: English
• Published: 01.06.2012
• Subjects: Line broadening; Nanocomposites; Nanomaterials; Nanostructure; Nanotechnology; Photoluminescence; Silicon; Ultraviolet
• ISSN: 2043-6262; 2043-6254; 2043-6262
• DOI: 10.1088/2043-6262/3/2/025002

Abstract Ultraviolet (UV) photoluminescence (PL) data taken on a double Au implanted Si matrix are reported. This has been studied over a wide temperature range of 28–220 K. At low temperature, the spectrum shows four peaks corresponding to a zero-phonon line (ZPL) and three low-energy phonon-assisted lines. At 28 K the ZPL has an energy of 3.362 eV with a lifetime of ∼240  ps suggesting transitions across a direct gap. The temperature variation of the ZPL intensity indicates an activation energy ∼10  meV comparable to the binding energy of excitons in crystalline Si (c-Si). For T > 100  K , it shows a redshift which can be understood as coming from exciton–phonon interaction. At lower temperatures the corresponding line broadening shows evidence of interaction with low-energy phonons of average energy ∼7  meV as suggested earlier. All the above results indicate the emission to be coming from Si nanoclusters (NCs) embedded in the matrix.