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Metal Filled Nanostructured Silicon With Respect to Magnetic and Optical Properties
摘要： Within this work the utilization of nanostructured silicon as host material with various magnetic nanostructures is reviewed whereas the magnetic and optical properties of the gained composite systems are elucidated. The metal filling of the pores is mainly performed by electroless deposition or by electrodeposition which is discussed by means of some examples. Furthermore, two different types of porous silicon (PSi) morphology are used for the deposition procedure. On the one hand microporous silicon offering luminescence in the visible range is utilized as template material. It offers a branched morphology with a structure size between 2 and 5 nm. In this case not only the magnetic response is investigated but also the influence of the metal filling on the optical properties. On the other hand mesoporous and macroporous silicon in it’s low pore regime is employed which offers straight pores with diameters up to 90 nm. In this case the magnetic response strongly depends on the size, the geometry and the spatial distribution of the metal deposits within the pores. A crucial role plays also the morphology of the porous silicon, especially the distance between adjacent pores which is an important parameter regarding magnetic interactions.
关键词： magnetic nanostructures,porous silicon,magnetic properties,electrodeposition,luminescence
更新于2025-09-23 15:19:57
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Formation of lipid bilayers on the pore walls of macroporous silicon
摘要： Electron paramagnetic resonance (EPR) spectroscopy was used to study the pore filling of macroporous silicon with lipid vesicles (liposomes), added with a spin label. Different EPR spectra were obtained with the magnetic field parallel and perpendicular to the macroporous silicon sample surface. These spectra could be well simulated with an admixture of the isotropic spectrum of liposomes, plus a simulated spectrum corresponding to a cylindrical distribution of lipid bilayers. This means that a portion of the liposomes were disrupted, and supported lipid bilayers were formed covering the inner surface of the pores. Diverse protocols can be explored in order to optimize the lipid covering of the pore walls, and to achieve an adequate lipid hydration. This system can be used as a platform to study lipid phase transitions in a confined environment, and to characterize membrane proteins.
关键词： Liposomes,Electron paramagnetic resonance/electron spin resonance,Supported lipid bilayers,Porous silicon,Spin labels
更新于2025-09-19 17:15:36
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Flow-Through Self-Standing Porous Silicon Sensor
摘要： A self-standing porous silicon (PS) multilayer structure detached from the substrate by the lift-off method and integrated with a microfluidic cell is presented. Experiments of refractive index changes sensing flow through open-ended pores are reported. We continuously recorded the reflectance spectra of the PS membrane each 30 s and measured the shift as different substances flowed through the structure. The experimental sensitivity values are in good agreement with the theoretical simulations performed.
关键词： membrane,self-standing film,lift-off,sensing,porous silicon,flow-through
更新于2025-09-19 17:15:36
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The Influence of Quantum Confinement on Third-Order Nonlinearities in Porous Silicon Thin Films
摘要： We present an experimental investigation into the third-order nonlinearity of conventional crystalline (c-Si) and porous (p-Si) silicon with Z-scan technique at 800-nm and 2.4-μm wavelengths. The Gaussian decomposition method is applied to extract the nonlinear refractive index, n2, and the two-photon absorption (TPA) coefficient, β, from the experimental results. The nonlinear refractive index obtained for c-Si is 7 ± 2 × 10?6 cm2/GW and for p-Si is ?9 ± 3 × 10?5 cm2/GW. The TPA coefficient was found to be 2.9 ± 0.9 cm/GW and 1.0 ± 0.3 cm/GW for c-Si and p-Si, respectively. We show an enhancement of the nonlinear refraction and a suppression of TPA in p-Si in comparison to c-Si, and the enhancement gets stronger as the wavelength increases.
关键词： Z-scan,third-order nonlinearity,TPA,porous silicon,self-focusing
更新于2025-09-19 17:15:36
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Enhancement of photodetectors devices for silicon nanostructure from study effect of etching time by photoelectrochemical etching technique
摘要： Porous silicon (PS) prepared from n-type silicon via photoelectrochemical etching (PECE) technique. The morphology properties of PS specimens that formed with different etching time has been study utilize Scanning electron microscopy (SEM) and it show that the Layer of pore has sponge like stricture and the average pore diameter of PS layer rising with increase etching time. The X-ray diffraction (XRD) pattern indicated the nanocrystaline of the specimens, during these results; we showed improve behavior of PS photodetectors on a range of wavelengths.
关键词： Morphological properties,Porous silicon,Photodetectors,Photoelectrochemical etching
更新于2025-09-19 17:13:59
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AIP Conference Proceedings [AIP Publishing THE 7TH INTERNATIONAL CONFERENCE ON APPLIED SCIENCE AND TECHNOLOGY (ICAST 2019) - Karbala City, Iraq (27–28 March 2019)] THE 7TH INTERNATIONAL CONFERENCE ON APPLIED SCIENCE AND TECHNOLOGY (ICAST 2019) - Investigations of ZnO-NiO/PSi heterojunction for solar cell application
摘要： In this paper, ZnO-NiO nanocomposite has been successfully synthesized using chemical precipitation method .The structural properties were investigated using X-ray diffraction ( XRD) and field emission scanning electron microscope (FESEM) . XRD measurements confirms the formation of polycrystalline ZnO and NiO nanoparticles with a hexagonal and cubic structure respectively. The average grain size of ZnO-NiO nanocoposite estimated from FESEM was 60 nm . Heterojunction solar cell fabricated using ZnO-NiO nanocomposite on porous silicon by spray pyrolysis method shows open-circuit voltage (VOC) of 470 mV, short-circuit current density (ISC) of 39 mA/cm2, fill factor (FF) of 78.72% , and efficiency of 14.43%.
关键词： porous silicon,solar cell,chemical precipitation,ZnO-NiO nanocomposite,spray pyrolysis
更新于2025-09-19 17:13:59
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MBE growth of InAs/GaAs quantum dots on sintered porous silicon substrates with high optical quality??in the 1.3 ??m band
摘要： We report self-assembled InAs/GaAs quantum dots (QDs) monolithically grown on a compliant transferable silicon nanomembrane. The transferable silicon nanomembrane with flat continuous crystalline silicon layer formed via in situ porous silicon sintering is considered a low-cost seed for heteroepitaxy of free-standing single-crystalline foils for photovoltaic cells. In this paper, the compliant feature of transferable silicon nanomembrane has been exploited for direct growth of high-quality InAs/GaAs (QDs) by molecular beam epitaxy. Bright 1.3 μm room temperature photoluminescence from InAs/GaAs QDs has been obtained. The excellent structural and optical qualities of the obtained InAs/GaAs quantum dots offer great opportunities for realizing a low-cost and large-scale integration of III–V-based optoelectronic device on silicon.
关键词： optoelectronic devices,InAs/GaAs quantum dots,molecular beam epitaxy,sintered porous silicon,photoluminescence
更新于2025-09-19 17:13:59
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In-depth study of annealed porous silicon: Understand the morphological properties effect on negative LiB electrode performance
摘要： Silicon (Si) used as negative electrode in a Li-ion battery (LIB) is highly attractive for its high energy density, safe cycling, and nontoxicity. However its alloying mechanism with Li induces material pulverization, which leads to a rapid capacity fade. In this work, annealing post treatment was used in order to tune the morphological properties of porous silicon. Playing on annealing temperature, the morphological modification induces electrochemical behavior changes in LIB. The porosification is an interesting way to accommodate the volume expansion occurring during the alloying process. Increase of the annealing temperature leads to porous Si pores and walls reorganization, which has a positive impact on battery performance likely due to a higher wettability of the Si electrode with electrolyte. 700 °C appeared to be the optimized annealing temperature.
关键词： Negative electrode,Morphological properties,Li-ion battery,Annealing,Silicon,Electrochemical behavior,Porous silicon
更新于2025-09-16 10:30:52
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The Enhanced Sensitivity of a Porous Silicon Microcavity Biosensor Based on an Angular Spectrum Using CdSe/ZnS Quantum Dots
摘要： To improve the detection sensitivity of porous silicon microcavity biosensors, CdSe/ZnS quantum dots are used to label complementary DNA molecules for the refractive index amplification and angular spectrum method for detection. In this method, the TE mode laser is used as the detection light and the light source is changed into a parallel beam by collimating and expanding the beam, which illuminates the PSM surface and receives the reflected light from the PSM surface through the detector. The angle corresponding to the weakest reflected light intensity before and after the biological reaction between probe DNA and complementary DNA of different concentrations labeled by quantum dots was measured by the detector, and the relationship between the angle change before and after the biological reaction and the complementary DNA concentration labeled by quantum dots was obtained. The experimental results show that the angle change increases linearly with increasing complementary DNA concentration. The detection limit of the experiment, as determined by fitting, is approximately 36 pM. The detection limit of this method is approximately 1/300 of that without quantum dot labeling. Our method has a low cost because it does not require the use of a reflectance spectrometer, and it also demonstrates high sensitivity.
关键词： refractive index amplification,angular spectrum,quantum dot,porous silicon microcavity
更新于2025-09-16 10:30:52
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Performance of thin silicon solar cells with a quasi-monocrystalline porous silicon layer on the rear side
摘要： The present study employs porous silicon (PS) or quasi-monocrystalline porous silicon (QMPS) as a reflector material on the rear side. It presents an analytical model that simulates the performance of n+–p–p+ thin silicon solar cell with a QMPS layer on the rear side. The development of the model involves the formulation of a complete set of equations for the photo-current density that is then solved analytically in the base region, including the photocurrent generated under the effect of the light reflected by QMPS layer. This also takes the contribution of the back p+-region (back surface field) to the generated photocurrent into consideration. The enhancements brought by the thin film QMPS with regard to photovoltaic (PV) parameters are then investigated and compared to those brought by the conventional silicon solar cell. Moreover, the effect of the QMPS layer on the current–voltage characteristics J–V and the internal quantum efficiency (IQE) of thin silicon solar cells are simulated by means of AFORS-HET software. These simulations show that the improvement of the PV parameters is due to an increase in the transport parameters of minority carriers in the p-region.
关键词： porous silicon,thin silicon solar cells,quasi-monocrystalline porous silicon,photovoltaic parameters,AFORS-HET software
更新于2025-09-12 10:27:22