A5084747531- Photonic and Optical Devices
- Photonic Crystals and Applications
- Silicon Nanostructures and Photoluminescence
- Thin-Film Transistor Technologies
- Silicon and Solar Cell Technologies
- Semiconductor Lasers and Optical Devices
- Advanced Fiber Laser Technologies
- Optical Coatings and Gratings
- Advanced Fiber Optic Sensors
- Nanowire Synthesis and Applications
- Optical Network Technologies
- solar cell performance optimization
- Gold and Silver Nanoparticles Synthesis and Applications
- Laser Material Processing Techniques
- Semiconductor materials and devices
- Electrochemical Analysis and Applications
- Advanced MEMS and NEMS Technologies
- Surfactants and Colloidal Systems
- Advanced Surface Polishing Techniques
- Force Microscopy Techniques and Applications
- Ionic liquids properties and applications
- Advanced Thermoelectric Materials and Devices
- Thermal Radiation and Cooling Technologies
- Organometallic Complex Synthesis and Catalysis
- Additive Manufacturing and 3D Printing Technologies
University of Southampton
2014-2021
Forschungszentrum Jülich
1996-2007
Bolometers are thermal detectors widely applied in the mid-infrared (MIR) wavelength range. In an integrated sensing system on chip, a broadband scalable bolometer absorbing light over whole MIR range could play important role. this work, we have developed waveguide-based operating of 3.72–3.88 µm amorphous silicon (a-Si) platform. Significant improvements design result <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mn>20</mml:mn> <mml:mo>×</mml:mo>...
The structure of organoaluminum(halide) complexes, used as cocatalysts in Ziegler−Natta catalysis, is investigated by experimental far-infrared spectroscopy and quantum simulations. Experimental calculated spectra agree very well, holding promise for the employed far-infrared/quantum simulation approach to reveal more detail on catalytically active site catalysis. Whereas species preferably form dinuclear aluminum complexes when bridge can be formed chlorine, basis total energies observed...
We demonstrate low-loss hydrogenated amorphous silicon (a-Si:H) waveguides by hot-wire chemical vapor deposition (HWCVD).The effect of hydrogenation in a-Si at different temperatures has been investigated and analyzed Raman spectroscopy.We obtained optical quality a-Si:H waveguide deposited 230°C that a strong peak shift 480 cm -1 , width FWHM 68.9 bond angle deviation 8.98°.Optical transmission measurement shows low propagation loss 0.8 dB/cm 1550 nm wavelength, which is the first to our...
We present interlayer slope waveguides, designed to guide light from one level another in a multi-layer silicon photonics platform. The waveguide is fabricated hydrogenated amorphous (a-Si:H) film, deposited using hot-wire chemical vapor deposition (HWCVD) at temperature of 230°C. comprises lower input and an upper output waveguide, connected by on slope, with vertical separation isolate other crossing waveguides. Measured loss 0.17 dB/slope was obtained for dimensions 600 nm width (w) 400...
We fabricated and measured the optical loss of polysilicon waveguides deposited using hot-wire chemical vapor deposition at a temperature 240°C. A film 220 nm thick was on top 2000 plasma-enhanced silicon dioxide layer. The crystalline volume fraction by Raman spectroscopy to be 91%. propagation losses 400, 500, 600 were 16.9, 15.9, 13.5 dB/cm, respectively, for transverse electric mode wavelength 1550 nm. Scattering is expected major contributor loss.
We report the fabrication of low-loss, low temperature deposited polysilicon waveguides via laser crystallization. The process involves pre-patterning amorphous silicon films to confine thermal energy during crystallization phase, which helps control grain growth and reduce heat transfer surrounding media, making it compatible with CMOS integration. Micro-Raman spectroscopy, Secco etching X-ray diffraction measurements reveal high crystalline quality processed formation millimeter long...
Surface-enhanced Raman spectra of cetylpyridinium bromide (CPB) adsorbed on a roughened polycrystalline silver electrode are reported as function the applied potential using microscope with Nd:YAG laser excitation source. The compared both to normal corresponding solid and solution species ab initio calculated spectrum N-methylpyridinium. assignment molecular bands is given in spectral range 100−3500 cm-1. Examining frequency shifts changes relative intensities CPB due adsorption variation...
Polysilicon piezoresistors with a large longitudinal gauge factor (GF) of 44 have been achieved using in-situ boron doped hot-wire chemical vapour deposition (HWCVD). This GF is consequence high quality p-type polysilicon crystal volume 97% and an average grain size 150 nm, estimated Raman spectroscopy atomic force microscopy (AFM) respectively. The measured minimum Hooge associated to the 1/f noise 1.4 × 10−3. These results indicate that HWCVD suitable piezoresistive material for...
We report nonlinear optical characterization of cm-long polycrystalline silicon (poly-Si) waveguides at telecom wavelengths. Laser post-processing lithographically-patterned amorphous deposited on silica-on-silicon substrates provides low-loss poly-Si with surface-tension-shaped boundaries. Achieving losses as low 4 dB cm-1 enabled us to demonstrate effects self-phase modulation (SPM) and two-photon absorption (TPA). Analysis the spectral broadening numerical modeling reveals best fit values...
Several 3D multilayer silicon photonics platforms have been proposed to provide densely integrated structures for complex circuits. Amongst these platforms, great interest has given the inclusion of nitride layers achieve low propagation losses due their capacity providing tight optical confinement with scattering in a wide spectral range. However, none demonstrated integration active devices. The problem is that typically loss fabricated LPCVD which involves high processing temperatures...
We report on the characterization of heavily boron doped epitaxial silicon regions grown in a hot-wire chemical vapor deposition tool, using micro-Raman and photoluminescence spectroscopy. In particular, use this approach for emitter fabrication an interdigitated back contact solar cell is studied, by analyzing its suitability concerning selective growth, uniformity, anneal time, luminescent defects. show that reducing silane flow rate, both required postanneal time intensity defect...
In this paper, we present morphological and electrical characteristics of a junction formed Si p-type films deposited on an n-type silicon wafer using hot wire chemical vapor deposition (HWCVD) tool. We describe the fabrication process study influence diborane flow postprocess annealing in improving characteristics. Our studies undertaken atomic force microscopy show that initial suffered from voids rather than being uniform film; however, improves significantly under our treatment. The...
In this work different silicon photonic devices, including straight waveguides, multi-mode interference devices and Mach-Zehnder interferometers, were fabricated characterized on hot-wire chemical vapor deposition (HWCVD) nitride (SiN) layers deposited at temperatures below 350 °C. These presented a hydrogen concentration of 13.1%, which is lower than that achieved with plasma enhanced these temperatures. The lowest reported optical propagation losses 6.1 dB/cm 5.7 dB/cm, 1550 nm 1310...
We present a method for the production of polycrystalline Si (poly-Si) photonic micro-structures based on laser writing.The consists local laser-induced crystallization amorphous silicon (a-Si) followed by selective etching in chemical agents that act preferentially a-Si material, consequently revealing poly-Si content film.We have studied characteristics these structures as function processing parameters and we demonstrate their potential functionality fabricating ridge optical...
In this talk, silicon photonics is introduced together with its opportunities in producing highly efficient optical interconnects. An overview of recent advancements the building block component development and integration these components both each other electronic devices to form functional photonic circuits given.The paper then presents some remaining challenges for researchers worldwide approaches which can answer needs.
We demonstrate low temperature hot-wire chemical vapor deposition of loss a-Si:H wire waveguides. achieved propagation 0.65 dB/cm at TE polarized 1.55 μm wavelength for waveguides deposited 230 °C.