ORCID Profile
0000-0002-3429-4911
Current Organisation
Consiglio Nazionale delle Ricerche
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Publisher: Springer Science and Business Media LLC
Date: 10-1996
DOI: 10.1007/BF02464691
Publisher: Springer Science and Business Media LLC
Date: 1996
DOI: 10.1557/PROC-422-239
Abstract: Hydrogenated amorphous silicon thin films, co-doped with oxygen, are made using lowpressure chemical vapor deposition (LPCVD) or plasma-enhanced chemical vapor deposition (PECVD). The films are implanted with Er to a peak concentration of 0.2 at.%. Roomtemperature photoluminescence at 1.54 μm is observed in both amorphous materials, after thermal annealing at 300–400 °C. The PECVD films with low 0 content (0.3, 1.3 at.%) show a luminescence intensity quenching by a factor 7–15 as the temperature is raised from 10 K to room temperature. The quenching is well correlated with a decrease in luminescence lifetime, indicating that non-radiative decay of excited Er 3+ is the dominant quenching mechanism as the temperature is increased. In the LPCVD films, with 31 at.% 0, the quenching is only a factor 3, and no lifetime quenching is observed. The results are interpreted in the context of an impurity Auger excitation model, taking into account the fact that oxygen modifies the Si bandgap and the Er-related defect levels in the gap.
Publisher: AIP Publishing
Date: 15-08-1995
DOI: 10.1063/1.360125
Abstract: The photoluminescence of erbium-doped semi-insulating polycrystalline and amorphous silicon containing 30 at. % oxygen is studied. The films were deposited on single-crystal Si substrates by chemical vapor deposition, implanted with 500 keV Er to fluences ranging from 0.05 to 6×1015 ions/cm2, and annealed at 300–1000 °C. Upon optical pumping near 500 nm, the s les show room-temperature luminescence around 1.54 μm due to intra-4f transitions in Er3+, excited by photogenerated carriers. The strongest luminescence is obtained after 400 °C annealing. Two classes of Er3+ can be distinguished, characterized by luminescence lifetimes of 170 and 800 μs. The classes are attributed to Er3+ in Si-rich and in O-rich environments. Photoluminescence excitation spectroscopy on a s le with 1×1015 Er/cm2 shows that ∼2% of the implanted Er is optically active. No quenching of the Er luminescence efficiency is observed between 77 K and room temperature in this Si-based semiconductor. The internal quantum efficiency for the excitation of Er3+ via photogenerated carriers is 10−3 at room temperature. A model is presented which explains the luminescence data in terms of trapping of electrical carriers at localized Er-related defects, and subsequent energy transfer to Er3+ ions, which can then decay by emission of 1.5 μm photons.
Publisher: AIP Publishing
Date: 04-10-1993
DOI: 10.1063/1.110608
Abstract: Semi-insulating polycrystalline silicon films with oxygen concentrations in the range 4–27 at. % were deposited by low-pressure chemical vapor deposition of SiH4 and N2O onto silicon substrates, annealed at 920 °C, and then implanted with 2×1015 500 keV Er ions/cm2. After annealing at temperatures in the range 300–900 °C, the s les show intense room-temperature luminescence around 1.54 μm, characteristic of intra-4f emission from Er3+, upon excitation using an Ar ion laser. The luminescence intensity increases with increasing oxygen concentration in the film. The luminescence is attributed to Er3+ ions in oxygen-rich shells around Si nanograins, excited by a photocarrier-mediated process.
Publisher: Elsevier BV
Date: 03-1995
Publisher: Springer Science and Business Media LLC
Date: 1996
DOI: 10.1557/PROC-422-333
Abstract: It is demonstrated room-temperature electroluminescence at 1.54 μm in erbiumimplanted oxygen doped silicon (27 at. 0), due to intra-4f transitions of the Er 3+ . The luminescence is electrically stimulated by biasing metal-(Si:O,Er)-p + silicon diodes. The 30 nm thick Si:O,Er films are amorphous layers deposited onto silicon substrates by chemical vapour deposition of S i H 4 and N 2 0, doped by ion implantation with Er to a concentration up to ≈ 1.5 at.%, and annealed in a rapid thermal annealing furnace. The most intense electroluminescence is obtained in s les annealed at 400°C in reverse bias under breakdown condition and it is attributed to impact excitation of erbium by hot carriers injected from the Si into the Si:O,Er layer. The electrical characteristics of the diode are studied in detail and related to the electroluminescence characteristics. A lower limit for the impact excitation cross-section of ≈6×10 −16 cm 2 is obtained.
Publisher: AIP Publishing
Date: 15-06-1995
DOI: 10.1063/1.359059
Abstract: Room-temperature electroluminescence at 1.54 μm is demonstrated in erbium-implanted oxygen-doped silicon (27 at. % O), due to intra-4f transitions of the Er3+. The luminescence is electrically stimulated by biasing metal-(Si:O, Er)-p+ silicon diodes. The 30-nm-thick Si:O, Er films are amorphous layers deposited onto silicon substrates by chemical-vapor deposition of SiH4 and N2O, doped by ion implantation with Er to a concentration up to ≊1.5 at. %, and annealed in a rapid thermal annealing furnace. The most intense electroluminescence is obtained in s les annealed at 400 °C in reverse bias under breakdown conditions and it is attributed to impact excitation of erbium by hot carriers injected from the Si into the Si:O, Er layer. The electrical characteristics of the diode are studied in detail and related to the electroluminescence characteristics. A lower limit for the impact excitation cross section of ≊6×10−16 cm2 is obtained.
Publisher: Elsevier BV
Date: 08-1996
No related grants have been discovered for Salvatore Lombardo.