•Inter-layer mixing, atomic redistribution, structural change, and phase transformation on AlN/TiN multilayers via argon ion irradiation.•Severe modifications are observed with TEM studies on highly ...immiscible alternating layers without any side effects such as beam heating.•The original TiN layers appear to grow in thickness by consuming the adjacent AlN layers, while obtaining a better TiAlN fcc crystalline structure.•Photoemission spectroscopy/microscopy indicates a transformation into Al deficient ternary and highly homogeneous compounds on both layers.•These results can be interesting towards further development of radiation tolerant materials based on immiscible ceramic nanocomposites.
This paper reports on compositional and structural modifications induced in coated AlN/TiN multilayers by argon ion irradiation. The initial structure consisting of totally 30 alternate AlN (8nm thick) and TiN (9.3nm thick) layers was deposited on Si (100) wafers, by reactive sputtering. Irradiation was done with 180keV Ar+ to a high dose of 8×1016 ions/cm2, which introduces up to ∼10at.% of argon species, and generates a maximum displacement per atom of 92 for AlN and 127 for TiN, around the projected ion range (109±34nm). Characterizations were performed by Rutherford backscattering spectrometry, spatially resolved x-ray photoelectron spectroscopy, and transmission electron microscopy. The obtained results reveal that this highly immiscible and thermally stable system suffered a severe modification upon the applied ion irradiation, although it was performed at room temperature. They illustrate a thorough inter-layer mixing, atomic redistribution, structural change and phase transformation within the affected depth. The original TiN layers appear to grow in thickness, consuming the adjacent AlN layers, while retaining the fcc crystalline structure. In the mostly affected region, the interaction proceeds until all of the original AlN layers are consumed. Compositional studies with photoemission spectroscopy show that due to the ion irradiation treatment the TiN and AlN layers are transformed into Ti0.75Al0.25N and Ti0.65Al0.35N ternary compounds characterized by a better homogenized chemical form compared to non-irradiated layers. The results can be interesting towards further development of radiation tolerant materials based on immiscible ceramic nanocomposites.
Room temperature electroluminescence in the eye safe region of the spectrum over the range 1.7–2.1 μm is demonstrated from a thulium doped silicon diode. The same room temperature photoluminescence ...can be attained on a silicon-on-insulator substrate. The emission lines are from the first excited to ground state of the Tm3+ ion, 3F4→3H6. A detailed study has been made to establish the optimum implant and processing conditions for efficient room temperature luminescence. The importance of the correct placement of the thulium ions with respect to the depletion region edge and dislocation loops formed upon boron implantation has been established. Tm3+ has been demonstrated to lase in other systems and is the basis of widely applied, commercial, optically pumped 2 μm lasers. The demonstration of electroluminescence in silicon and luminescence on an SOI platform are necessary prerequisites for the potential development of Tm injection lasers and optical amplifiers.
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•Silicon light emitting diode at 2.1 μm achieved by ion implanting of thulium ions using standard silicon processing.•Room temperature (RT) electroluminescence is demonstrated under forward bias with a low one volt turn on voltage.•RT photoluminescence on an SOI platform is demonstrated, offering potential route towards an electrically pumped Tm laser.•Optimum process for dislocation loops to confine carriers to prevent surface recombination and enable RT luminescence.
The thermodynamic properties and phase diagrams of the Ru–Si and Os–Si systems are assessed. The calculated enthalpies of fusion and entropies of fusion of ruthenium and osmium silicides are compared ...with the reported values of different transition metal silicides. Both the thermodynamic properties and the phase diagrams of Ru–Si and Os–Si systems are in good agreement with the available experimental data.
The influence of boron-induced dislocation loops on the luminescence efficiency of silicon-based light-emitting diodes is investigated. Luminescence measurements and transmission-electron-microscopy ...images from devices fabricated by boron implantation into crystalline silicon, and subsequently processed under different conditions to form dislocation loops of different size and densities, were compared. Light emitting devices were also fabricated in an otherwise identical but a pre-amorphized substrate, to prevent boron-induced loop formation. The results demonstrate a strong correlation between the dislocation loop density and areal coverage, and the light emission efficiency. The devices produced in the pre-amorphized substrate, without dislocation loops, show strongly quenched light emission.
In this paper, a general overview of the technologies surrounding light emission in silicon-based systems is presented with an indication as to the applications for which they may be used. Special ...attention is given to the use of dislocation engineering, where, through the use of additional dopants, not only can 1150-nm band edge emission be achieved but tuning of the wavelength to accommodate telecommunications applications is also possible. Details of the impact of implantation energy and dose are demonstrated together with post implant anneal studies to optimise the process for light generation. Finally, dislocation engineering is applied to silicon on insulator (SOI), the most common optical platform.
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