- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Functionalized and oxidized silicon nanosheets: Customized design for enhanced sensitivity towards relative humidity
摘要： The use of completely oxidized two-dimensional (2D) silicon nanosheets (SiNSs) represents a novel approach for the application of 2D silicon-based materials in the nanoelectronics field. Densely stacked and highly porous oxidized SiNSs (OSiNSs) act as a sensitive layer for humidity detection. Due to the oxidation-caused porosity of the SiNSs and the possibility functionalize the 2D surface with hydrophilic groups, this hybrid material exhibits an extremely good sensitivity towards relative humidity (RH). In this work, precise tuning of the SiNSs’ sensing properties by their functionalization is demonstrated. In particular, the modification with methacrylic acid (MAA) groups, leading to SiNS-MAA, and the subsequent deposition on interdigitated electrodes double the capacitance value in the range of 20-85%RH. These values were achieved after the full oxidation of SiNS-MAA in ambient conditions. The mentioned changes in capacitance are extremely high compared to the response of the so far known common polymer humidity sensors. Contrary to that, this response is neutralized when the SiNSs are functionalized with tert-butyl acrylic acid (tBMA), a rather hydrophobic functional group. The fabricated devices show, how the specific functionalization of SiNSs serves as a reliable tool to provide sensitivity towards RH. Similar approach, based on tuning the functionality, can be applied to achieve e.g., sensor array selectivity. For this purpose, the functional groups on the surface of the nanomaterial can be further modified. Additional molecules with sensitivities towards various surrounding conditions could be attached. Furthermore, these functional molecules can be used for subsequent (bio)molecule immobilization, which can serve as sensitive molecular groups towards surrounding substrates and gases. However, one of the main challenges in sensor technology is to find a highly selective solution: a sensor system capable to differentiate among different vapor species. The described strategy can serve as an access towards new and promising solutions, which can help to face this issue in modern nanomaterials-based technology.
关键词： two-dimensional materials,porous silicon,functionalization,silicon nanosheets,hybrid systems,moisture content
更新于2025-11-21 11:20:48
-
Quasi-one-dimensional silicon nanostructures for gas molecule adsorption: a DFT investigation
摘要： Porous structures offer an enormous surface suitable for gas sensing, however, the effects of their quantum quasi-confinement on their molecular sensing capacities has been seldom studied. In this work the gas-sensing capability of silicon nanopores is investigated by comparing it to silicon nanowires using first principles calculations. In particular, the adsorption of toxic gas molecules CO, NO, SO2 and NO2 on both silicon nanopores and nanowires with the same cross sections was studied. Results show that sensing-related properties of silicon nanopores and nanowires are very similar, suggesting that surface effects are predominant over the confinement. However, there are certain cases where there are remarked differences between the nanowire and porous cases, for instance, CO-adsorbed nanoporous silicon shows a metallic band structure unlike its nanowire counterpart, which remains semiconducting, suggesting that quantum quasi-confinement may be playing an important role in this behaviour. These results are significant in the study of the quantum phenomena behind the adsorption of gas molecules on nanostructure’s surfaces, with possible applications in chemical detectors or catalysts.
关键词： Sensing,Chemical sensors,Silicon nanowires,Density functional theory,Molecule adsorption,Porous silicon
更新于2025-09-23 15:23:52
-
NIR light-triggered gelling <i>in situ</i> of porous silicon nanoparticles/PEGDA hybrid hydrogels for localized combinatorial therapy of cancer cells
摘要： Porous silicon-based nanocomposite hydrogels were readily constructed with the gelation of poly(ethylene glycol) double acrylates (PEGDA) macromers, due to the initiation of singlet oxygen photosensitized with porous silicon nanoparticles (PSiNPs) under near-infrared (NIR) light irradiation. Multifunctional PSiNPs/PEGDA nanocomposite hydrogels showed strong ?uorescence, excellent biodegradability, signi?cant photothermal effect, and sustained drug release with high ef?ciency (>80%). Finally, in situ growth of PSiNPs/PEGDA hybrid hydrogels on cancer cells was also achieved by NIR light, and then their biodegradation, drug release and synergistic chemo-phototherapeutic ef?cacy were further demonstrated, which could provide a signi?cant localized inhibition for the viability, adherence, and migration of cancer cells in vitro. Thus, we suggested that these resultant hybrid hydrogels would have important potential on local cancer therapy in future clinical practice.
关键词： porous silicon nanoparticles,hybrid hydrogels,therapy,insitu gelation,localized cancer
更新于2025-09-23 15:23:52
-
Determination of Selectivity Coefficients of Sodium and Potassium Ion-Selective Electrode Using Porous Silicon N-Type (100) Based Extended Gate Field Effect Transistor
摘要： Determination of Selectivity Coefficients of Sodium and Potassium Ion-Selective Electrode Using Porous Silicon N-Type (100) Based Extended Gate Field Effect Transistor
关键词： Sodium,Selectivity Coefficients,Porous Silicon,Extended Gate Field Effect Transistor,Ion-Selective Electrode,Potassium
更新于2025-09-23 15:23:52
-
Investigation of Strongly Hydrophobic and Thick Porous Silicon Stain Films Properties
摘要： Porous silicon (PSi) structures with strong hydrophobicity have been achieved by chemical etching of p-type silicon substrates in a solution based on hydrofluoric acid solution (HF) and vanadium oxide (V2O5). The surface morphology and microstructure of the elaborated structured silicon surfaces were investigated using Scanning Electron Microscope (SEM), contact angle and Fourier Transform Infrared spectroscopy (FTIR). The results show that the obtained structures exhibit hierarchically porous surfaces with porous pillars of silicon (PPSi) and an important hydrophobicity of the surface. The electrical properties of those PPSi structures were investigated in presence of 10 ppm of NO2 gas. The response time was about 30s at room temperature. Our results demonstrate that PPSi/Si are highly hydrophobic for long time and suitable for applications in the field of self-cleaning and may be a good candidate in elaborating practical NO2 sensors.
关键词： Porous silicon,Hydrophobicity,Gas sensing applications,Pillars structures
更新于2025-09-23 15:23:52
-
Electrical Properties of Porous Silicon for N2 Gas Sensor
摘要： The application of porous silicon (PSi) for gas sensing devices has gained a considerable attention in the last decade. This work considers the electrical features of PSi layers prepared by electrochemical etching. We find that in order to get a better understanding of the absorption properties of PSi surface, it is necessary to know how the PSi morphology depends on the etching parameters. The physical structure of PSi, i.e., porosity, and pore size distribution can be controlled by changing the Hydrofluoric Acid concentration, current density, anodizing length and etching time in anodizing procedure. We describe our test system for gas sensors and investigate on the electrical behavior of PSi layers (p-type) in N2 gas for various fabrication conditions. The results show that the current density increases significantly as N2 gas is adsorbed. The measurements of the I-V characteristics were carried out at atmospheric pressure, room temperature, and with N2 gas as well.
关键词： Current-voltage curve,N2 gas,Porous silicon,Gas sensor
更新于2025-09-23 15:23:52
-
Improved galvanic porous silicon fabrication using patterned electrodes
摘要： On-chip porous silicon can be fabricated in a number of ways, but perhaps the simplest is a galvanic method that requires no external power supply. While this etch process is relatively simple, the etch is highly dependent on the surface area ratio (SAR) of a backside precious metal and frontside silicon surface, which respectively act as the cathode and the anode of an electrochemical cell. The SAR controls the etch current density, and therefore local variations can create high current densities that have detrimental effects on the quality of the final porous silicon film. The present study investigates the use of patterned backside platinum electrodes with the galvanic etch technique. The use of a patterned backside electrode that mimics the silicon pattern on the frontside, provides a more consistent etch current throughout the entire sample, and thus a more uniform porous silicon film. A triangular shape porous silicon film was tested in this work for comparison to a previous study utilizing an unpatterned electrode. With patterned electrodes, an etch depth variation percentage was observed throughout the length of the film of 8%. This is a considerable improvement over a 108% depth variation observed with a similar frontside silicon pattern and an unpatterned backside electrode.
关键词： porous silicon,electrochemical etching,mesoporous,galvanic etching
更新于2025-09-23 15:23:52
-
Electrical and Photoelectrical Characteristics of с-Si/Porous–Si/CdS Heterojunctions
摘要： Depending on the sizes of the CdS crystallites and silicon pores, electrical and photoelectrical characteristics of c-Si/porous–Si/CdS heterojunctions prepared by electrochemical deposition and anodization, respectively, are studied. The optimal pore size (10–16 nm) is determined, which provides the maximum photoelectric conversion efficiency (7.71%) of heterojunctions.
关键词： porous silicon,heterojunction,anodization,electrochemical deposition
更新于2025-09-23 15:22:29
-
Selective Gas Sensor Using Porous Silicon
摘要： The effect of polar and non-polar vapors, like ethanol, methanol, acetonitrile, chloroform and toluene vapors on porous silicon gas sensor was studied. We demonstrated that the selectivity of a single sensor can be achieved by the impedance measurements within the frequency range 103–105 Hz. It is shown that the capacitance of the structure and its frequency dispersion are different under influence of different gases providing an unique signature of an agent. A set of parameters is proposed in order to numerically characterize the response to different gases. The characteristic time of response to different vapors gives an additional parameter to sense gases selectively.
关键词： Organic Vapors,Gas Sensor,Porous Silicon,Selectivity
更新于2025-09-23 15:22:29
-
Properties of Porous Silicon Precipitated with Nickel for Gas Sensors
摘要： The preparation and properties of modified porous silicon is discussed and a proposal of a sensitive layer for a gas detector is presented. The modification is done by precipitation and electrochemical deposition of nickel. The morphology of sample surfaces is examined by atomic force microscopy and scanning electron microscopy (SEM). SEM-coupled energy dispersive spectroscopy is used to analyse the chemical composition of the samples. Magnetic response is measured with a SQUID magnetometer. Electrochemical impedance spectroscopy is used to study the sensitivity of the samples to isopropanol vapour in the presence of alternating electric current. A series of samples prepared with a higher anodic current density show higher sensitivity to isopropanol vapours in comparison to a lower anodic current.
关键词： Electrochemical Impedance Spectroscopy,Porous Silicon,Gas Sensors,SQUID,Electroless Nickel Deposition,Atomic Force Microscopy
更新于2025-09-23 15:22:29