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Current Controlled Switching in Si/PS/a-Si Heterostructure
摘要： Current controlled switching has been observed in p-type crystalline Silicon (p-c-Si)/porous Si (PS)/n-type hydrogenated amorphous Silicon (n-a-Si:H) heterostructure. Mechanism of the switching is proposed consideringpresence of trapped carriers at the silicon nanocrystal-SiOx interface. A part of the trapped charges are considered to be bound near the n-a-Si:H/PS and PS/p-c-Si interface forming an additional coulomb barrier for the majority carriers. It is assumed that during the flow of current through the PS layer, the captured carriers get de-trapped by impact-excitation leading to breaking of the barrier after certain threshold value resulting in the switching. This model matches well with the experimental results.
关键词： amorphous silicon,interface,porous silicon,Switching
更新于2025-09-12 10:27:22
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Two-Dimensional Fluorescent Strategy Based on Porous Silicon Quantum Dots for Metal-Ion Detection and Recognition
摘要： A two-dimensional photoluminescent (2D PL) detection strategy was established based on luminescent porous silicon (LuPSi) with wide-size-distributed silicon quantum dots and abundant surface chemistry. Owing to the intrinsic nature of LuPSi, interaction or reaction between analytes and LuPSi may cause static, dynamic, oxidation-induced, and deposition-induced quenching. By monitoring of both the PL intensity change and peak shift of LuPSi, the 2D PL detection strategy could discriminate di?erent analytes. Detection and recognition of di?erent metal ions in real water samples using a single peak were realized. Compared with the existing array-based methods, the 2D PL approach signi?cantly simpli?ed the sensing element and detection process.
关键词： metal ions,quantum dot array,two-dimensional photoluminescence,luminescent porous silicon,recognition
更新于2025-09-12 10:27:22
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Pulsed-laser-deposited lead sulfide nanoparticles based decoration of porous silicon layer as an effective passivation treatment for multicrystalline silicon
摘要： We report on the use of pulsed laser deposition (PLD) of PbS nanoparticles (PbS-NPs) on porous silicon layers in order to passivate multicrystalline silicon (mc-Si) substrates intended for solar cells applications. The porous silicon (PS) layer was first obtained through the electrochemical anodization of the mc-Si substrate, and then the PLD technique was used to decorate the PS layer by PbS-NPs at room temperature. By varying the number of laser ablation pulses (NLP) from 50 to 1200, the average size of the PbS-NPs was varied from ~2 nm to ~10 nm. The X-ray diffraction analysis has confirmed the crystalline quality of the PbS-NPs, whereas the transmission electron microscopy observations showed the uniform decoration of the PS by the PbS-NPs. By combining different characterization techniques, we were able to identify NLP = 200 as the optimal decoration condition that leads to the best passivation, in terms of the lowest surface reflectivity (of 15% at 500 nm wavelength), the highest PL intensity of the PS layer (centered around 633 nm) and the longest minority carrier lifetime (as long as ~430 μs versus 40 μs for the bare treated PS layer and 2.2 μs for the untreated bare mc-Si).
关键词： Pulsed laser deposition,Porous silicon,Solar cells,PbS nanoparticles,Surface passivation
更新于2025-09-12 10:27:22
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Fabrication and investigation of hybrid Perovskite solar cells based on porous silicon
摘要： The present work is a study of the effect of incorporating (CuO/PbI2/CH3NH3I/ZnO) on the porous silicon (p-Psi) by using the drop casting technique procedure at a temperature of 70 (cid:1)C. Structural, optical and morphological properties of (p-PSi, CuO, and ZnO) nanoparticles were characterized by X-ray diffraction, UV–Vis spectrophotometer, scanning electron microscopy and atomic force microscopy. The estimated optical energy value of thin films (CuO, PbI2, and ZnO) was (3.87, 2.3, and 4.1 eV), respectively. The results of the current–voltage test manifested that the maximum power conversion efficiency (PCE) of the solar cell was 8.21%, and the filling factor was 41.4%. This research is revealing and investigating the successful hybrid Perovskite solar cells based on the porous silicon.
关键词： Porous silicon,Perovskite,PCE,Nanoparticle,FSEM
更新于2025-09-12 10:27:22
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[IEEE 2019 European Space Power Conference (ESPC) - Juan-les-Pins, France (2019.9.30-2019.10.4)] 2019 European Space Power Conference (ESPC) - Space III-V Multijunction Solar Cells on Ge/Si virtual substrates
摘要： Virtual substrates based on thin Ge layers on Si substrates by direct deposition have recently achieved high quality. In this work, their application as low cost, removable substrates for the growth of high efficiency, lightweight and flexible multijunction solar cells for space applications is analyzed. Experimental Ge single-junction solar cells and GaInP/Ga(In)As/Ge triple-junction solar cells using the Ge/Si virtual substrate as an active bottom junction (being the Si inactive), are implemented using medium quality Ge/Si virtual substrates with a 5 μm Ge layer thickness. A lower quality in the Ge material, as compared to standard substrates, but enough carrier collection efficiency for a standard triple-junction, are shown. The expected formation of cracks during growth, due to the large thermal expansion coefficient mismatch with the Si substrate, is confirmed, and is found to be a major limiting factor for the performance of the solar cells. Strategies such as thinning the Ge + III-V structure and minimizing the thermal cycling during growth are discussed. Using an embedded porous Si layer to serve as buffer for the strain is being investigated. This porous layer could also serve as sacrificial layer for high throughput mechanical epitaxial lift-off in the manufacturing of lightweight and flexible multijunction cells. These embedded porous Si layers need to be engineered for optimum performance and compatibility with the Ge and III-V deposition processes.
关键词： lightweight solar cell,III-V multijunction solar cell,porous silicon,virtual substrate
更新于2025-09-12 10:27:22
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Improving the photoelectrical conversion efficiency of silicon solar cells using ZnO:Al/porous silicon double antireflective layers
摘要： In this work, porous silicon (PS) layers are performed on the front side of n+p wafer via electrochemical etching technique (etching times of 15 and 25 min), using isopropanol as solvent, followed by covering with Al-doped ZnO (AZO) films prepared by sol–gel spin-coating method. AZO/PS double layers are found to have incomparable photoluminescence and reflectance characteristics required for the use as antireflection. The structural, optical properties of PS, AZO and AZO/PS have been investigated. The results show that the energy bandgap of PS layer is higher than that of nonporous Si and increases slightly with increasing the etching time. X-ray diffraction shows that the prepared AZO films have nanostructure character with hexagonal structure. The optical properties of AZO films are studied in terms of measuring the transmittance and reflectance over wavelength range 200–2500 nm. Using these parameters, the absorption coefficient and refractive index of AZO films are calculated and the related parameters are estimated. AZO films deposited on PS/n+p exhibit low reflectance compared to n+p and AZO/n+p systems. The improvement of the solar cells performance due to the effect of porosity and AZO films deposition are investigated in which the solar cells parameters are evaluated and discussed.
关键词： Porous silicon,Solar cells,Antireflective layers,Photoelectrical conversion efficiency,Al-doped ZnO
更新于2025-09-12 10:27:22
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Synthesis of Graphene on Porous Silicon for Vapor Organic Sensor by Using Photoluminescence
摘要： In this work, ultra-sensors of chemical solvents vapor were fabricated for chloroform, n-Hexane and Ethanol via modified porous silicon (PS) surface by the reduction of graphene oxide (rGO) layer. The rGO was conducted by electrochemical exfoliation of graphite electrodes with electrolyte solution at PH=4.6. Then porous silicon (PS) was prepared by employing electrochemical etching (ECE) method using silicon (Si) p-type at different etching current density J= 2, 4 and 6mA/cm2with constant HF concentration of 15%, and time of etching of 15min. The reduction graphene oxide competition with PS was studied as vapors organic sensor, morphological, structural, and surface bond configuration were characterized by Atomic Force Microscopic (AFM), X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) respectively, then the Photoluminescence (PL) quenching was measured by using sensor test system with three types of organic chemical solvents n-Hexane, chloroform and ethanol with nitrogen gas mixing, where they were prepared for testing humidity sensor towards the different organic solvents. The results revealed that the reduction graphene oxide layer on surface of PS lead to intensity increase of the PL, and modified the quality of PS sensor for chemical vapor.
关键词： porous silicon,organic vapor sensor,Photoluminescence,Graphene
更新于2025-09-11 14:15:04
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Reconstructing charge-carrier dynamics in porous silicon membranes from time-resolved interferometric measurements
摘要： We performed interferometric time-resolved simultaneous reflectance and transmittance measurements to investigate the carrier dynamics in pump-probe experiments on thin porous silicon membranes. The experimental data was analysed by using a method built on the Wentzel-Kramers-Brillouin approximation and the Drude model, allowing us to reconstruct the excited carriers’ non-uniform distribution in space and its evolution in time. The analysis revealed that the carrier dynamics in porous silicon, with ~50% porosity and native oxide chemistry, is governed by the Shockley-Read-Hall recombination process with a characteristic time constant of 375 picoseconds, whereas diffusion makes an insignificant contribution as it is suppressed by the high rate of scattering.
关键词： carrier dynamics,porous silicon,Drude model,Shockley-Read-Hall recombination,interferometric measurements
更新于2025-09-11 14:15:04
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AIP Conference Proceedings [Author(s) INTERNATIONAL CONFERENCE ON INVENTIVE MATERIAL SCIENCE APPLICATIONS: ICIMA-2018 - Tamil Nadu, India (27–28 September 2018)] - The effect of the ZnO thickness layer on the porous silicon properties deposited by chemical vapor deposition
摘要： We report on the properties of porous silicon deposited by Electro-Chemical Etching (ECE) technique with ZnO nanoparticles layer grown on porous silicon (P-type) by Chemical Vapor Deposition (CVD). X-ray diffraction study on the crystallographic structure revealed a beneficial impact of ZnO films on the structural properties of the porous silicon. Moreover, these properties enhanced when the ZnO layer thickness was increased. The morphological properties of ZnO/PSi were investigated based on Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) measurements. The results indicate an upgrading in the structural stability of PSi substrate with crystalline growth of ZnO thin film. It is also observed that the value of the roughness (RMS) increases when ZnO filme on PSi increases. All these results indicate that the interested ZnO shows a good and homogenous layer using (CVD) technique. Finally, it is evident that porous silicon substrate can open the door for improving the crystalline quality in hexagonal lattice of ZnO thin film, and this could be due to sponge-like structure of porous silicon.
关键词： ZnO,porous silicon,SEM,Chemical Vapor Deposition,AFM,Electro-Chemical Etching,XRD
更新于2025-09-10 09:29:36
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Effect of porous silicon substrate on structural, mechanical and optical properties of MOCVD and ALD ruthenium oxide nanolayers
摘要： Ruthenium oxide (RuO2) has received significant attention in recent years for its photocatalytic properties and photoelectrochemical (PEC) performance. In the present research, RuO2 nanolayers were grown on n-type porous silicon (PSi) by metal organic chemical vapor deposition (MOCVD) and atomic layer deposition (ALD). The morphology, mechanical and optical properties of produced nanostructures were studied by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), micro-Raman spectroscopy, diffuse reflectance and photoluminescence (PL) spectroscopy. It was shown that that MOCVD gives non-uniform distribution of RuO2 along the pore and it is deposited mainly in the near-surface of PSi, while distribution of ruthenium obtained by ALD looks conformal over the entire pore. The mean size of RuO2 nanocrystallites and mechanical stresses were determined by TEM, XRD and Raman spectroscopy. It was demonstrated that samples obtained by ALD demonstrate a good crystallinity, while crystalline phase for samples produced by MOCVD improve with RuO2 layer thickness increasing. It was established the formation of hydrated RuO2 during ALD and MOCVD. It was shown that the samples produced by MOCVD have slightly higher electrical conductivity than ALD samples. The average value of energy gap (Eg) for samples prepared by MOCVD depended on the number of injections. RuO2 nanolayers quenched intrinsic PL from the PSi matrix. The correlation between structural, optical, and mechanical properties of samples produced by MOCVD and ALD was discussed.
关键词： MOCVD.,ruthenium oxide,ALD,porous silicon
更新于2025-09-10 09:29:36