We have fabricated erbium-doped porous silicon (PSi) devices and demonstrated stable room-temperature electroluminescence (EL) at 1.54 μm under both forward and reverse bias conditions. Erbium was infiltrated into th...
We have fabricated erbium-doped porous silicon (PSi) devices and demonstrated stable room-temperature electroluminescence (EL) at 1.54 μm under both forward and reverse bias conditions. Erbium was infiltrated into the nanostructured matrix of PSi (≤ 10 19 cm —3 ) by cathodic electrochemical migration of the ions followed by high temperature annealing (950–1100 °C). The devices exhibit an exponential EL dependence in both bias conditions as a function of driving current and voltage. External quantum efficiencies of 0.01% have been obtained. The EL intensity in reverse bias and the transport properties of the devices show large temperature dependences. From the differences in temperature, electrical, and EL characteristics in forward and reverse biases, we believe that different excitation mechanisms are responsible for the EL.
In this study we present the fabrication, the optical characterization and the electrical operation of a high quality, nanometer-sized, silicon-based light modulator made of nematic liquid crystals (LC) encapsulated i...
In this study we present the fabrication, the optical characterization and the electrical operation of a high quality, nanometer-sized, silicon-based light modulator made of nematic liquid crystals (LC) encapsulated into porous silicon (PSi) multilayer matrix. We first demonstrate the infiltration procedure and characterize the cell's reflectance and photoluminescence (PL) before and after infiltration. Then we examine the LC molecular alignment, and show that their long axis is positioned along the pore walls. Therefore, the electrical control of an interference filter is achieved by applying a field horizontal to the pore's directionality. We also demonstrate that by applying up to 10 V the molecules reorient, the effective refractive index is modulated by as much as Δ n = 0.15, and the reflectance spectra is red shifted.
A variety of alternate training strategies for implementing the dual heuristic programming (DHP) method of approximate dynamic programming in the neurocontrol context are explored. The DHP method of controller trainin...
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A variety of alternate training strategies for implementing the dual heuristic programming (DHP) method of approximate dynamic programming in the neurocontrol context are explored. The DHP method of controller training has been successfully demonstrated by a number of authors on a variety of control problems in recent years, but no unified view of the implementation details of the method has yet emerged. A number of options are described for sequencing the training of the controller and critic networks in DHP implementations. Results are given about their relative efficiency and the quality of the resulting controllers for two benchmark control problems.
We apply the modal distribution, a high-resolution time-frequency distribution, to the study of sung musical passages. Evidence is presented comparing the modal distribution with the spectrogram for a set of synthetic...
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An integrated multichannel wavelength monitoring circuit using specially designed phased-array waveguide grating and detector arrays, which monitors all wavelength-division multiplexing channels in real-time (sixteen ...
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ISBN:
(纸本)155752582X
An integrated multichannel wavelength monitoring circuit using specially designed phased-array waveguide grating and detector arrays, which monitors all wavelength-division multiplexing channels in real-time (sixteen channels at 200-GHz spacing), has been demonstrated with /spl sim/0.02 nm accuracy.
We developed an alternate method for density-based load estimation and applied it to estimate hip joint load distributions for two femora. Two-dimensional finite element models were constructed from single energy quan...
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In this article, we have studied the role of photoeffects in the formation of aluminum back surface field (BSF) contacts on p-type silicon wafers by using different lamp configurations in rapid thermal processing (RTP...
In this article, we have studied the role of photoeffects in the formation of aluminum back surface field (BSF) contacts on p-type silicon wafers by using different lamp configurations in rapid thermal processing (RTP). Use of photons of wavelengths less than 800 nm in conjunction with infrared and visible photons in RTP resulted in the reduction of processing time from 202 to 138 s and the processing temperature from 890 to 850 °C. The reduction in the overall thermal budget used for BSF contact formation is a direct result of photon assisted RTP. The availability of a large number of high energy photons on the metal surface also resulted in improved electrical, structural and mechanical properties of the processed device.
We address the problem of efficient circuit switching in wide area networks. The solution provided is based on finding optimal routes for lightpaths and semilightpaths. A lightpath is a fully optical transmission path...
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We address the problem of efficient circuit switching in wide area networks. The solution provided is based on finding optimal routes for lightpaths and semilightpaths. A lightpath is a fully optical transmission path, while a semilightpath is a transmission path constructed by chaining several lightpaths together, using wavelength conversion at their junctions. The problem thus is to find an optimal lightpath/semilightpath in the network in terms of the cost of wavelength conversion and the cost of using the wavelengths on links. We first present fast, efficient algorithms both for the general problem and for a natural restricted version. The new algorithms outperform earlier work, providing time improvements amounting to an almost linear time factor in most cases. Also, all our algorithms can be implemented on the network in a distributed way.
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