Photoluminescence characterization of Si-based nanostructured films produced by pulsed laser ablation

Abstract

Articles you may be interested inMulti-band photoluminescence in TiO2 nanoparticles-assembled films produced by femtosecond pulsed laser deposition J. Appl. Phys. 114, 043503 (2013); 10.1063/1.4816251Morphology, structure, chemical composition, and light emitting properties of very thin anodic silicon films fabricated using short single pulses of current Photoluminescence ͑PL͒ properties of nanostructured Si-based films produced by pulsed laser ablation in a residual gas are studied. Two types of PL signals have been identified. Signals of the first type are sensitive to the ablation conditions with the PL peak position depending on the gas pressure during the deposition. Signals of the second type with PL peaks around 1.6 -1.7 and 2.2-2.3 eV are almost independent of the ablation conditions and are mainly determined by the presence of oxygen-related complexes in the film composition. These complexes can be formed through a prolonged natural oxidation or thermal annealing of the films, or through the direct laser ablation in the presence of oxygen. Possible mechanisms of PL signals are discussed.

Photoluminescence of highly porous nanostructured Si-based thin films deposited by pulsed laser ablation

“…The average size of the Si particles, measured as the atomic force microscopy ͑AFM͒ height, is below 10 nm. 26 However, the PL peak position varies, depending on the deposition conditions, [24][25][26] similar to what was reported for porous Si produced by other methods. 15,21,22,27 Here, we examine the PL behavior of PLD-deposited Si-based nanoporous SiO x /Si ͑natural oxide formed on Si͒, SiN x , and SiO x thin films, having completely different chemistries and microstructures.…”

“…͑3͒ These two PL bands are generally believed to arise from different mechanisms: the 2.3-eV band is thought to arise from the defect-related SiO x layer 24,25,51-57 through the recombination of carriers at defects ͑"defects luminescence"͒, while the 1.5-eV band is attributed to the recombination of confined excitons in Si nanoparticles ͑"quantum confinement"; however, see item ͑1͒ above͒. 24,25,[52][53][54][55][56][57] Many researchers have noted that the 2.3-eV band invariably appears in heavily oxidized defect-containing Si, including bulk and nanostructured thin films; given that this is so, we would expect, in the case of the short-time oxidation of SiN x , in Fig. 3, that the 2.3-eV peak would be substantially weaker than in Si and SiO x , something that is not found.…”

“…[19][20][21][22][23][24][25] PLD is performed at relatively low gas pressures, 0.1-10 torr, in the presence of either inert or reactive gases. During expansion and cooling, condensation begins within the ablated vapor; the condensed particles undergo multiple collisions with ambient gas molecules, leading to the energy stabilization of the nanoparticles before they arrive at the substrate surface.…”

<title>Air optical breakdown on silicon as a novel method to fabricate photoluminescent Si-based nanostructures</title>

“…The search of methods for the production of visible light-emission from Si-based materials becomes currently a great task and a subject of numerous studies (see, e.g., Refs. [1][2][3][4][5][6][7][8][9][10][11][12][13][14].…”

“…This nanostructuring could be produced b anodical etching of a silicon wafer in HF solutions 1 or by a deposition of nanocluster Si-based films through different "dry" methods such as, for example, magnetron sputtering 2 , laser breakdown of silane 3 , pulsed laser ablation [4][5][6][7][8] etc. Though the anodical etching enables one to produce nanostructured silicon with the most intense photoluminescence emission, "dry" fabrication methods are considered as more adequate for creating optoelectronics devices due to their better potential compatibilit with silicon processing technology.…”