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In this work, the fabrication of an acoustic sound absorbing surface (i.e. liner) made of commercial Visaton™ K16 microspeakers is presented. The acoustic liner is made of a circular surface composed of a 10 cm diameter fix support with 7 embedded microspeakers covering 8.5% of th overall surface. Different electrical connections of the microspeakers using no added electronic circuit are tested and...
This work focuses on the development of integrated front side film stack containing a-p Si:H film as the emitter and ITO film as the carrier collection layer in n-type silicon heterojunction (SHJ) solar cells. Doping concentration and thickness of a-p Si:H films, and O2/Ar flow ratio of DC sputtered ITO films were varied to obtain optimal single layer properties. A combined ITO/double a-p Si:H stack...
A photonic crystal based on a macroporous silicon structure has been fabricated and successfully used for the detection of carbon dioxide. In this paper, the device and the measurement results are presented. The sensing device here described uses an optical approach to the detection of the gas. The use of a photonic crystal allows creating a compact device working in the medium infrared spectral range...
The characteristics of reflection and transmission peaks in the spectra of photonic crystals have been studied theoretically and the results compared to measurements performed in fabricated samples. The aim of this work is to investigate the relation between material losses and the effective Q factors that can be obtained in photonic crystals made with it. Photonic crystals have been designed with...
We investigate the enhancement of optical absorption in thin-film microcrystalline silicon solar cell by creating multiple resonant modes based on photonic crystal band-edge effect. Experimentally, 1.3 times increase of photo-current is observed, and theoretically it is shown that ultimately more than 9.6% conversion efficiency could be possible even with only “500nm” microcrystalline silicon with...
Combining quantum well intermixing and multiple die bonding a broadband superluminescent III-V on silicon LED was realized. Balancing four LEDs with different band gaps resulted in 292nm 3dB bandwidth and an on-chip power of −8dBm.
There is an expanding interest in finding novel concepts for increasing the efficiency and reduce the cost in solar cell devices. In this regard, semiconductor nanowires (NWs) provide various paths towards both goals. In this work we explore the increased device freedom offered by nanowires for optimizing carrier extraction and light absorption in solar cells.
We describe nanophotonic design approaches for broadband light management including i) crossed-trapezoidal Si structures ii) Si photonic crystal superlattices, and iii) tapered and inhomogeneous diameter III-V/Si nanowire arrays.
This paper reports on the optical and electrical characteristics of III-nitride epi-structures for visible wavelength absorption. Structures, incorporating InxGa1−xN/GaN (0.20<x<0.35) quantum well active regions have been analysed by photocurrent spectroscopy, optical transmission and electro/photo-luminescence techniques to identify the key spectral absorption characteristics of the structures...
The effect of decoupled front/back textures and the application of photonic and plasmonic nanostructures on the performance of thin silicon solar cells was studied. New light trapping concepts based on diffraction on periodic photonic nanostructures and scattering using plasmonic structures have potential to outperform the currently used randomly textured structures. The study demonstrates that supporting...
The optical properties of the silicon hexagonal nanoconical hole (SiHNH) arrays based solar cells is systematically studied via simulation based on Rigorous Coupled Wave Analysis (RCWA) and Modal Transmission Line (MTL) theory. An ultimate efficiency of the optimized SiHNH arrays based solar cell is up to 31.92%, 4.52% higher than that of silicon hexagonal nanoconical frustum (SiHNF) arrays. The absorption...
Semiconductor nanowires and nanostructures have a great potential for Terahertz generation and detection, especially because certain materials properties such as optical absorption, high electron and hole mobility, and short carrier lifetime can be engineered through structural changes and material compositions. In such structures, the variation in geometry and surface charge characteristics can greatly...
In this work an ARC based GaAs solar cell having both homojunction and heterojunction has been simulated. The cell structure consist of TCO/a-Si:H(p)/GaAs(p)/GaAs(n)/a-Si:H(n)/TCO. The structure has been simulated using Silvaco TCAD. This structure gives higher fill factor due to the reduced series resistance and hence results better efficiency. The work function of the transparent conductive oxide...
We have carried out an experimental and theoretical study of the optical transmittance in terahertz to infrared regime of graphene multilayer on Si substrate under moderate electric field. It is shown that graphene multilayer on Si substrate has low resistance at room temperature, less than that of the silicon alone. The theoretical and experimental results also show good convergence at short and...
Influence of thermal effects induced by nonlinear absorption on four-wave mixing in silicon waveguides is investigated. A conversion bandwidth reduction up to 63% is observed in simulation due to the thermal effects.
We present the design for a MIR integrated source based on the thermal emission of a heated silicon waveguide. With a temperature of 1000 K a total power of 0.47 μW can be achieved.
On-chip and off-chip optical interconnections have been expected to breakthrough the scaling bottleneck of the microprocessors. The missing link is dense-wavelength-division-multiplexed (DWDM) technology. The high index contrast, Si on insulator (SOI) platform, here after referred to as HiDex, is excellent to shrink the footprint of devices and circuits. However, HiDex has a fundamental limit to implement...
We report nonlinear measurements of SiGe waveguides in the mid-IR performed in the picosecond and femtosecond regime and compare the results to numerical calculations. Nonlinear properties of SiGe waveguides in the mid-IR are extracted.
We demonstrated a method for fabricating edge-conformed silicon-graphene waveguides on an SOI chip. Transmission measurements showed large waveguide attenuation of 0.1dB/μm for TM and 0.036dB/μm for TE mode due to strong optical absorption of graphene.
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