Morphology of Porous Silicon Nanostructures in p-type Silicon Based on Novel Comparison between Two Electrochemical Cells Design (original) (raw)
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Iraqi Journal of Science, 2019
The influence of anodization time with the electrochemical cell design on the fabrication process of porous silicon (PS) nanostructures based on two electrochemical anodization cells (designed single tank cell and double tank cell) with two anodization times (10 and 30 minutes) was studied. Atomic force Microscopy (AFM) characterization had revealed three types of pores, mesopores, mesopore fill of mesopores, and macropore fill of mesopores were obtained from designed single tank cell with (10 and 30 minutes) of anodization time, whilst for double tank cell has not revealed precise information about the size and type of pores. Pores formation have been further approved by current-voltage (I-V) measurement and photoluminescence emission by ultraviolet-lamp (254-366) nm for both electrochemical cells.
Materials Science Forum, 2013
Porous silicon (p-Si) is a well-known silicon based material that can emit visible light at room temperature. The radiative recombination that originated from quantum confinement effect shows photoluminescence (PL) in red, while the defect on silicon oxide at the surface of p-Si shows in blue-green region. Porous silicon can be synthesized through two methods; wet-etching and electrochemical anodization using hydrofluoric acid as the main electrolyte. The electrochemical anodization is more favorable due to faster etching rate at the surface than the conventional wetetching method. The objective of this research is to show that both of porous silicons can be synthesized using the same main electrolyte but by varying the reaction environment during anodization/etching process. Here, we shows the wet-etching method that enhanced by polarization concentration will produce porous silicon with silicon oxide defects by means blue-green emission, while direct electrochemical anodization will produce samples that emit red PL signal. The effect of introducing KOH into the electrolyte was also studied in the case of enhanced-wet-etching method. Surface morphology of porous silicon and their photoluminescence were observed by Scanning Electron Microscope and PL spectroscopy, respectively.
Materials Science Forum, 2013
Porous silicon (p-Si) is a well-known silicon based material that can emit visible light at room temperature. The radiative recombination that originated from quantum confinement effect shows photoluminescence (PL) in red, while the defect on silicon oxide at the surface of p-Si shows in blue-green region. Porous silicon can be synthesized through two methods; wet-etching and electrochemical anodization using hydrofluoric acid as the main electrolyte. The electrochemical anodization is more favorable due to faster etching rate at the surface than the conventional wetetching method. The objective of this research is to show that both of porous silicons can be synthesized using the same main electrolyte but by varying the reaction environment during anodization/etching process. Here, we shows the wet-etching method that enhanced by polarization concentration will produce porous silicon with silicon oxide defects by means blue-green emission, while direct electrochemical anodization will produce samples that emit red PL signal. The effect of introducing KOH into the electrolyte was also studied in the case of enhanced-wet-etching method. Surface morphology of porous silicon and their photoluminescence were observed by Scanning Electron Microscope and PL spectroscopy, respectively.
Malaysian Journal of Fundamental and Applied Sciences
Achieving high quality porous silicon (PSi) materials with desired porosity remains challenging. Three good qualities of PSi samples are prepared by Photo electro-chemically etching a piece of n-type Si inside the solution of 20 M HF, 10 M C2H5OH and 10 M H2O2 at fixed etching time duration (30 min) and varying current density (15 mA/cm2, 30 mA/cm2 and 45 mA/cm2). As-prepared sample morphologies are characterized via scanning electron microscopy (SEM) and atomic force microscopy (AFM). The gravimetric method is used to estimate the thickness and porosity of the prepared samples. Current density (etching time) dependent morphologies, electronic bandgap and room temperature photoluminescence (PL) properties of such PSi nanostructures are evaluated. These PSi structures revealed enhanced rectifying characteristics with increasing current density.
Synthesis of Porous Silicon Nanostructures for Photoluminescent Devices
2001
Porous structures were formed on p-Si wafers under various anodization conditions in ethanolic solutions containing aqueous hydrofluoric acid. The observed photoluminescence at room temperature depends on the anodization current density and the anodization time. Polyaniline (PA) was incorporated into the pores of the porous silicon (PSi) structure by in-situ electrodeposition. The porous structure formation has been confirmed using XRD and
I-V and C-V Characteristics of Porous Silicon Nanostructures by Electrochemical Etching
2013
Porous silicon (PS) layers has been prepared in this work by electrochemic al etching (ECE) technique of a p-type silicon wafer with resistivity (1.5-4 Ω.cm) in hydrofluoric (HF) acid of 20% concentration. Various affecting studied etching time (10, 30, and 45 min) and current density (15 mA/cm 2 ). We have study the morphological properties (AFM) and the electrical properties (I-V and C-V). The atomic force microscopy investigation shows the rough silicon surface, with increasing etching process (etching time) porous structure nucleates which leads to an increase in the depth and width (diameter) of surface pits. Consequently, the surface roughness also increases. The electrical properties of prepared PS; namely current density-voltage characteristics under dark, show that the pass current through the PS layer decreased by increasing the etching time, due to increase the resistivity of PS layer. The PS layer shows a rectifying behaviour with different rectification ratio. C-V measu...
Journal of Nanomaterials, 2014
Luminescent porous silicon (Psi) fabricated by simple chemical etching technique in different organic solvents was studied. By quantifying the silicon wafer piece, optical properties of the Psi in solutions were investigated. Observation shows that no photoluminescence light of Psi in all solvents is emitted. Morphology of Psi in different solvents indicates that the structure and distribution of Psi are differently observed. Particles are uniformly dispersive with the sizes around more or less 5–8 nm. The crystallographic plane and high crystalline nature of Psi is observed by selected area diffraction (SED) and XRD. Electronic properties of Psi in solutions are influenced due to the variation of quantity of wafer and nature of solvent. Influence in band gaps of Psi calculated by Tauc’s method is obtained due to change of absorption edge of Psi in solvents. PL intensities are observed to be depending on quantity of silicon wafer, etched cross-section area on wafer surface. Effects ...
Characteristics of Nanostructure Porous Silicon Prepared by Anodization Technique
2013
Porous silicon (PS) layers are prepared by anodization for different current densities. The samples are then characterized the nanocrystalline porous silicon layer by X-Ray Diffraction (XRD), Atomic Force Microscopy (AFM), Fourier Transform Infrared (FTIR), Reflectivity and Raman. PS layers were formed on a p-type Si wafer. anodized electrically with a 10 and 40 mA/cm 2 current density for fixed 20 min etching times. We have estimated crystallites size from X-Ray diffraction about nanoscale for porous silicon and AFM confirms the nanometric size and therefore optical properties about nanocrystalline silicon yields a Raman spectrum showing a broadened peak shifted below 520 cm -1 .
International Journal of Modern Physics B, 2015
Effects of current density on nanostructure and light emitting properties of porous silicon (PS) samples were investigated by field emission scanning electron microscope (FE-SEM), gravimetric method, Raman and photoluminescence (PL) spectroscopy. FE-SEM images have shown that below 60 mA/cm 2, macropore and mesopore arrays, exhibiting rough morphology, are formed together, whose pore diameter, pore depth and porosity are about 265–760 nm, 58–63 μ m and 44–61%, respectively. However, PS samples prepared above 60 mA/cm 2 display smooth and straight macropore arrays, with pore diameter ranging from 900–1250 nm, porosity of 61–80% and pore depth between 63–69 μ m . Raman analyses have shown that when the current density is increased from 10 mA/cm 2 to 100 mA/cm 2, Raman peaks of PS samples shift to lower wavenumbers by comparison to crystalline silicon (c-Si). The highest Raman peak shift is found to be 3.2 cm -1 for PS sample, prepared at 90 mA/cm 2, which has the smallest nanocrystall...
2010
Porous silicon (PS) is defined as a composition of a silicon skeleton permeated by a network of pores or in other word, PS is a network of silicon nanowires and nanoholes which are formed when the crystalline silicon wafers are etched electrochemically in electrolyte solution such as hydrofluoric (HF) acid . PS shows different features in comparison to the bulk silicon such as shifting of fundamental absorption edge into the short wavelength and photoluminescence visible region. The PS material possesses interesting characteristics such as larger surface to volume ratio, high-intensity of nano porous structure and low refractive index. This paper presents the synthesis and characterization of electrochemically anodized PS structures. The effect of short anodization time on the PS structures is investigated. The PS surface morphology and optical properties are characterized using scanning electron microscopy (SEM) and photoluminescence (PL) spectrometer, respectively.