Papers by Keyword: Porous Silicon (PS)

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Authors: N. Zouadi, N. Gabouze, D. Bradai, D. Dahmane
Abstract: The hydrogen-sensing property of new type field-effect gas sensor device was studied. The device had an FET structure based on porous silicon. Adsorption of molecules into the porous silicon strongly changes the electrical properties of the transistor structure. Interestingly, the current variation induced by Hydrogen gas vapour that is the sensitivity of the sensor can be electrically tuned by changing polarization voltage. It has been shown that the device exhibited excellent hydrogen-sensing characteristic at room temperature. The results show that current-voltage characteristics are modified by the gas reactivity on the PS surface. In conclusion, the FET gas sensor based on porous silicon shows a rapid response to low concentration of the hydrogen gas at room temperature.
Authors: Chi Yuan Lee, Shuo Jen Lee, Ching Liang Dai, Chih Wei Chuang
Abstract: This investigation utilizes porous silicon as the gas diffusion layer (GDL) in a micro fuel cell. Pt catalyst is deposited on the surface of, and inside the porous silicon, to improve the performance of a fuel cell, and the Pt metal that remains on the rib is used to form a micro thermal sensor in a single lithographic process. Porous silicon with Pt catalyst replaces traditional GDL, and the relationships between porosity and pore diameter, and the performance of the fuel cell are discussed. In this work, electrochemical etching technology is employed to form porous silicon to replace the gas diffusion layer of a fuel cell. This work focuses on porous silicon with dimensions of tens of micrometers. Porous silicon was applied to the gas diffusion layer of a micro fuel cell. Boron-doped 20 '-cm n-type (100)-oriented doubly polished silicon wafer was used on both sides. The process is performed to etch a fuel channel on one side of a silicon wafer, and then electrochemical etching was adopted to form porous silicon on the other side to fabricate one silicon wafer that combines porous silicon with a fuel channel on a silicon wafer to minimize a fuel cell. The principles on which the method is based, the details of fabrication flows, the set-up and the experimental results are all presented.
Authors: A.V. Vasin, Yukari Ishikawa, Noriyoshi Shibata, Jarno Salonen, Vesa Pekka Lehto
Abstract: In the present work, the carbonization of porous silicon for the subsequent 3C-SiC growth has been systematically studied. The effect of temperature and acetylene flow-rate on the chemical state of the surface and structure relaxation was studied. It was found that the porous nano-crystalline morphology is unstable and tends to recrystallize in temperature range typical of 3C-SiC growth on Si (10000C-13000C). The carbonization impedes recrystallization at 10000C, but at 13000C the full recrystallization takes place. Pyrolytic amorphous graphite-like carbon was found on porous silicon carbonized at temperature and with acetylene flow-rate above critical values.
Authors: B. Méndez, J. Piqueras, R. Plugaru, G. Craciun, N. Nastase, A. Cremades, E. Nogales
Authors: S. La Monica, Marco Balucani, S. Lazarouk, G. Maiello, G. Masini, P. Jaguiro, A. Ferrari
Authors: Hanna Bandarenka, Aliaksandr Shapel, Marco Balucani
Abstract: Cu-Si nanocomposites formed by an immersion displacement deposition of Cu into porous silicon (PS) matrix have been experimentally studied. SEM and AES were used to investigate the structure and elemental composition of Cu-Si samples. The top part of the Cu-PS samples is shown to demonstrate the following structure: large faceted Cu grains at the top, a porous fine-grained copper film underneath the large grains, and the copper pointed rods extended from the surface into the PS layer. The top part of the silicon skeleton of the PS layer is converted into the copper by the etching followed by Cu displacement deposition. The porosity of the porous layer and displacement deposition times are found to form Cu-Si nanocomposites of various structures and various Cu-Si contents because of various extent of the silicon skeleton transformation into copper.
Authors: Martin Stutzmann, Martin S. Brandt
Authors: Hans Jürgen von Bardeleben, A. Grosman, V. Morazzani, C. Ortega, J. Siejka
Authors: Xing Hua Qu, X.H. Zhao, S.H. Ye
Abstract: Porous silicon with pore size in the range of a few nanometers can be used as multifunctional material in different MEMS applications. Via an electrochemical etching method, porous silicon is fabricated on the silicon substrate and removed as a sacrificial layer by using KOH solution to form a micro structure. This technique is typical in micro fabrication. Three-dimensional size is the basic geometric feature to describe microstructure surface characteristics. It is important to investigate measurement methods for it. UBM Microfocus Measurement System based on defocusing error detection is adopted to measure eroded depth of silicon cup. The measured data in the experiments are analyzed. The influence of etching time, current density and silicon type on etching depth can be acquired. Effective reference data can be provided for studying micro fabrication methods.
Authors: Priyanka Singh, Shailesh N. Sharma, G. Bhagavannarayana, M. Husain, M. Lal
Abstract: Porous silicon (PS) layers were formed by anodization on polished substrates of (1 0 0) Si at different current densities for a fixed anodization time of 30 mins. using different screenprinted/ evaporated back contacts (Ag, Al) respectively. The PS films has been characterized by high resolution X-ray diffraction (HRXRD), photoluminescence (PL), Scanning Electron Microscopy (SEM) and Fourier Transform Infrared (FTIR) techniques respectively. Porosity and thickness of PS layers were estimated by gravimetric analysis. The properties of PS formed using screen-printed Ag & Al as the back contacts (SP-(Ag/Al)) was found to be superior as compared to the corresponding films with evaporated back contacts (EV-(Ag/Al)). The PS formed with screenprinted Ag & Al-back contacts shows better crystalline perfection, higher stability, higher PL efficiency and negligible PL decay compared to that formed with evaporated Ag & Al- as the back contact for the same current density and time of anodization.
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