Preparation of Porous Silicon and Effect of Gettering on the Resistivity

2012 ◽  
Vol 476-478 ◽  
pp. 1794-1797 ◽  
Author(s):  
Su Xia Guo ◽  
Yi Tan ◽  
Jia Yan Li ◽  
Ya Qiong Li ◽  
Chen Guang Liu
Keyword(s):  
Porous Silicon ◽  
Raman Spectra ◽  
Pore Diameter ◽  
Crystalline Silicon ◽  
Electrochemical Etching ◽  
Silicon Layer ◽  
Porous Silicon Layer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

The porous silicon layer was fabricated by electrochemical etching process using an aqueous HF-based electrolyte. The characterizations of porous silicon layer were investigated by Emission-type scanning electron microscope (SEM), Raman spectra and X-ray diffraction (XRD). With the current density increasing, the pore diameter and density become much bigger. This result also was confirmed by Raman spectra and XRD result of samples, which revealed the decreasing of grain size of silicon. The resistivity of crystalline silicon increased when the porous layer was removed after heat treatment at 850°C for 2.5h, which should be attributed to the gettering process of porous silicon.

Effects of Electrochemical Etching Time on the Performance of Porous Silicon Solar Cells on Crystalline n-Type (100) and (111)

2017 ◽  
Vol 46 ◽  
pp. 45-56 ◽  
Author(s):  
Khalid Omar ◽  
Khaldun A. Salman
Keyword(s):  
Solar Cells ◽  
Porous Silicon ◽  
Crystalline Silicon ◽  
Electrochemical Etching ◽  
Silicon Layer ◽  
Porous Silicon Layer ◽  
Silicon Solar Cells ◽  
Etching Time ◽  
Crystalline Silicon Solar Cells ◽  
Coating Layers

Electrochemical etching was carried out to produce porous silicon based on crystalline silicon n-type (100) and (111) wafers. Etching times of 10, 20, and 30 min were applied. Porous silicon layer was used as anti-reflection coating on crystalline silicon solar cells. The optimal etching time is 20 min for preparing porous silicon layers based on crystalline silicon n-type (100) and (111) wafers. Nanopores with high porosity were produced on the porous silicon layer based on crystalline silicon n-type (100) and (111) wafers with average diameters of 5.7 and 5.8 nm, respectively. Average crystallite sizes for the porous silicon layer based on crystalline silicon n-type (100) and (111) wafers were 20.57 and 17.45 nm at 20 and 30 min, respectively, due to the increase in broadening of the full width at half maximum. Photoluminescence peaks for porous silicon layers based on crystalline silicon n-type (100) and (111) wafers increased with growing porosity and a great blue shift in luminescence. The minimum effective coefficient of reflection was obtained from porous silicon layers based on the crystalline silicon n-type (100) wafer compared with n-type (111) wafer and as-grown at different etching times. Porous silicon layers based on the crystalline silicon n-type (100) wafer at 20 min etching time exhibited excellent light trapping at wavelengths ranging from 400 to 1000 nm. Thus, fabricated crystalline silicon solar cells based on porous silicon (100) anti-reflection coating layers achieved the highest efficiency at 15.50% compared to porous silicon (111) anti-reflection coating layers. The efficiency is characterized applying I-V characterization system under 100 mW/cm2 illumination conditions.

Investigation of optical anisotropy of refractive-index-profiled porous silicon employing generalized ellipsometry

1999 ◽  
Vol 14 (11) ◽  
pp. 4167-4175 ◽  
Author(s):  
S. Zangooie ◽  
R. Jansson ◽  
H. Arwin
Keyword(s):  
Porous Silicon ◽  
Optical Anisotropy ◽  
Optical Model ◽  
Crystalline Silicon ◽  
Electrochemical Etching ◽  
Silicon Layer ◽  
Porous Silicon Layer ◽  
Interface Roughness ◽  
Compositional Gradient ◽  
Time Modulation

Porosity depth profiles in porous silicon were realized by time modulation of the applied current density during electrochemical etching of crystalline silicon. The samples were investigated by variable angle spectroscopic ellipsometry. Using a basic optical model based on isotropy assumptions and the Bruggeman effective medium approximation, deviations from an ideal profile in terms of an interface roughness between the silicon substrate and the porous silicon layer and a compositional gradient normal to the surface were revealed. Furthermore, optical anisotropy of the sample was investigated by generalized ellipsometry. The anisotropy was found to be uniaxial with the optic axis tilted from surface normal by about 25°. The material was also found to exhibit positive birefringence.

X-Ray Diffraction and Reflectivity Studies of Thin Porous Silicon Layers

1996 ◽  
Vol 452 ◽  
Author(s):  
D. Buttard ◽  
G. Dolino ◽  
D. Bellet ◽  
T. Baumbach
Keyword(s):  
Porous Silicon ◽  
Structural Information ◽  
Surface Film ◽  
Silicon Layer ◽  
Lattice Parameter ◽  
Porous Silicon Layer ◽  
Interface Thickness ◽  
X Ray Diffraction ◽  
X Ray

AbstractHigh resolution X-ray diffraction and reflectivity have been used for the structural characterization of thin porous silicon layers of p and p+ doping type. Thin porous silicon layers studied either by diffraction or reflectivity, in the range of 10–1000 nm, exhibit several thickness fringes, corresponding to a lateral homogeneity of the layer thickness. The comparison between the experimental results with simulations enables one to deduce structural information relative to the porosity, thickness, lattice parameter as well as interface thickness. For p+ type samples a double fringe system was observed, showing the existence of a surface film probably at the porous silicon layer top surface.

scholarly journals Effect of photo chemical etching and electro chemical etching on the topography of porous silicon wafers surfaces

2019 ◽  
Vol 24 (4) ◽  
pp. 52
Author(s):  
Amjad Hussein Jassem
Keyword(s):  
Porous Silicon ◽  
Layer Thickness ◽  
Porous Layer ◽  
Chemical Etching ◽  
Chemical Method ◽  
Pore Diameter ◽  
Electrochemical Etching ◽  
Silicon Layer ◽  
Porous Silicon Layer ◽  
Etching Time

In This research we study the effect of photo chemical etching and electrochemical etching on topography of porous silicon surfaces, the results showed that photo chemical etching produced roughness silicon layer which can have thickness be less of porous silicon layer which is produced by electro chemical etching When all the wafers have same etching time  and hydrofluoric solution (HF) concentration, the wafers have same resistance (10 Ω.cm). Also the results showed the roughness of porous silicon layers produced  by  electro chemical method which is bigger than the roughness of porous silicon layers produced by photo chemical method and the results of roughness of porous silicon layers, Pore diameter and porous layer thickness were produced by electro chemical method (1.55(µm) ((0.99(µm)) and ((1.21(µm) respectively), the results of roughness of porous silicon layers, Pore diameter and porous layer thickness were produced by photo chemical method 0.63)) nm -1.55)) (µm) ),so the (84.9 (nm)- and (3.94(nm) respectively . This is reinforces because of using the electro chemical to etching the wafer surf ace of bulk silicon and changing it to roughness silicon surface  be share in success of many practicalities.   http://dx.doi.org/10.25130/tjps.24.2019.072

scholarly journals Porous silicon prepared by photo electrochemical etching assisted by laser

2019 ◽  
Vol 15 (32) ◽  
pp. 122-129
Author(s):  
Falah A-H Mutlak
Keyword(s):  
Porous Silicon ◽  
Current Density ◽  
Crystalline Silicon ◽  
Electrochemical Etching ◽  
Silicon Layer ◽  
Porous Silicon Layer ◽  
Maximum Diameter ◽  
Face Centered Cubic ◽  
The Face ◽  
Face Centered

Porous silicon (PS) layers are prepared by anodization fordifferent etching current densities. The samples are thencharacterized the nanocrystalline porous silicon layer by X-RayDiffraction (XRD), Atomic Force Microscopy (AFM), FourierTransform Infrared (FTIR). PS layers were formed on n-type Siwafer. Anodized electrically with a 20, 30, 40, 50 and 60 mA/cm2current density for fixed 10 min etching times. XRD confirms theformation of porous silicon, the crystal size is reduced towardnanometric scale of the face centered cubic structure, and peakbecomes a broader with increasing the current density. The AFMinvestigation shows the sponge like structure of PS at the lowercurrent density porous begin to form on the crystalline silicon, whenthe current density increases, pores with maximum diameter areformed as observed all over the surface. FTIR spectroscopy shows ahigh density of silicon bonds, it is very sensitive to the surroundingambient air, and it is possible to oxidation spontaneously.

scholarly journals Structural Studies of Zno Nanostructures on Porous Silicon: Effect of Post-Annealing Temperature

2018 ◽  
Vol 7 (3.11) ◽  
pp. 48
Author(s):  
Kevin Alvin Eswar ◽  
Mohd Husairi Fadzillah Suhaimi ◽  
Muliyadi Guliling ◽  
Zuraida Khusaimi ◽  
Mohamad Rusop ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Annealing Temperature ◽  
Electrochemical Etching ◽  
Texture Coefficient ◽  
Zno Nanostructures ◽  
Structural Studies ◽  
X Ray Diffraction ◽  
X Ray ◽  
Post Annealing ◽  
Post Annealing Temperature

ZnO Nanostructures have been successfully deposited on of Porous silicon (PSi) via wet colloid chemical approach. PSi was prepared by electrochemical etching method. ZnO/PSi thin films were annealed in different temperature in the range of 300 °C to 700 °C. Surface morphology studies were conducted using field emission scanning microscopy (FESEM). Flower-like structures of ZnO were clearly seen at annealing temperature of 500 °C. The X-ray diffraction spectra (XRD) have been used to investigate the structural properties. There are three dominant peaks referred to plane (100), (002) and (101) indicates that ZnO has a polycrystalline hexagonal wurtzite structures. Plane (002) shows the highest intensities at annealing temperature of 500 °C. Based on plane (002) analysis, the sizes were in range of 30.78 nm to 55.18. In addition, it was found that the texture coefficient of plane (002) is stable compared to plane (100) and (101). 

Effect of Au on the Performance of Porous Silicon/V2O5 Nanorods Heterojunctions to NO2 Gas

NANO ◽  
2016 ◽  
Vol 11 (07) ◽  
pp. 1650079 ◽  
Author(s):  
Wenjun Yan ◽  
Ming Hu ◽  
Jiran Liang ◽  
Dengfeng Wang ◽  
Yulong Wei ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Porous Silicon ◽  
Room Temperature ◽  
Au Nanoparticles ◽  
Analytical Techniques ◽  
Heating Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

A novel composite of Au-functionalized porous silicon (PS)/V2O5 nanorods (PS/V2O5:Au) was prepared to detect NO2 gas. PS/V2O5 nanorods were synthesized by a heating process of pure vanadium film on PS, and then the obtained PS/V2O5 nanorods were functionalized with dispersed Au nanoparticles. Various analytical techniques, such as field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), have been employed to investigate the properties of PS/V2O5:Au. Herein, the PS/V2O5:Au sample exhibited improved NO2-sensing performances in response, stability and selectivity at room temperature (25[Formula: see text]C), compared with the pure PS/V2O5 nanorods. These phenomena were closely related to not only the dispersed Au nanoparticles acting as a catalyst but also the p-n heterojunctions between PS and V2O5 nanorods. Whereas, more Au nanoparticles suppressed the improvement of response to NO2 gas.

I-V and Surface Topography Study of Nanostructure Porous Silicon Layer Prepared by Electrochemical Etching

2012 ◽  
Vol 576 ◽  
pp. 519-522 ◽  
Author(s):  
Fadzilah Suhaimi Husairi ◽  
Maslihan Ain Zubaidah ◽  
Shamsul Faez M. Yusop ◽  
Rusop Mahmood Mohamad ◽  
Saifolah Abdullah
Keyword(s):  
Electrical Properties ◽  
Porous Silicon ◽  
Surface Topography ◽  
Electrochemical Etching ◽  
Silicon Layer ◽  
Porous Silicon Layer ◽  
Force Microscopy ◽  
Atomic Force ◽  
Current Voltage ◽  
P Type

This article reports on the electrical properties of porous silicon nanostructures (PSiNs) in term of its surface topography. In this study, the PsiNs samples were prepared by using different current density during the electrochemical etching of p-type silicon wafer. PSiNs has been investigated its electrical properties and resistances for different surface topography of PSiNs via current-voltage (I-V) measurement system (Keithley 2400) while its physical structural properties was investigated by using atomic force microscopy (AFM-XE100).

Preparation and Characterization TiO2 Aerogel Fibers

2013 ◽  
Vol 743-744 ◽  
pp. 434-437
Author(s):  
Miao Lv ◽  
Guo Tong Qin ◽  
Wei Wei
Keyword(s):  
Electron Microscopy ◽  
Pore Diameter ◽  
Supercritical Drying ◽  
Mass Ratio ◽  
Composite Fibers ◽  
X Ray Diffraction ◽  
Average Pore ◽  
X Ray ◽  
Adsorption Desorption ◽  
Scanning Electron

TiO2aerogel fibers have been fabricated by electron span combined supercritical drying technique. Polyvinylpyrrolidone (PVP)/TiO2composite fibers are prepared by electrospinning PVP and TiO2precursor Ti (OC4H9)4. TiO2aerogel fibers are obtained by supercritical drying PVP/TiO2composite fibers using ethanol as media. Structural of the aerogel fibers was investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) and N2adsorption at 77 K. The effect of mass ratio of PVP/TiO2was investigated. SEM shows that pore structure of nanofibers was well developed, with the diameter of nanofibers about 2 μm. N2adsorption/desorption data show that the highest surface area of aerogel fibers reached 241.6 m2/g with the average pore diameter about 10 nm. The aerogel fibers were anatase type TiO2.

scholarly journals CONTROL OVER THE PERFORMANCE OF MONOCRYSTALLINE SILICON SOLAR CELLS REFERRING TO THE POROUS SILICON LAYER / MONOKRISTALINIO SILICIO SAULĖS ELEMENTŲ CHARAKTERISTIKŲ VALDYMAS AKYTOJO SILICIO SLUOKSNIU

2012 ◽  
Vol 3 (6) ◽  
pp. 91-94
Author(s):  
Ramūnas Mitkevičius ◽  
Viktor Zagadskij ◽  
Eugenijus Šatkovskis
Keyword(s):  
Solar Cells ◽  
Porous Silicon ◽  
Output Power ◽  
Crystalline Silicon ◽  
Silicon Layer ◽  
Porous Silicon Layer ◽  
Silicon Solar Cells ◽  
Crystalline Silicon Solar Cells ◽  
Maximal Output Power ◽  
Maximal Output

The paper examines the parameters of crystalline silicon solar cells such as fill factor, maximal output power and series resistance forming a porous silicon layer. The obtained results show that introducing the layer into the structure of a solar cell results in a 19 percent enhancement of maximal output power and conversion efficiency. Santrauka Šiame darbe tiriamas akytojo silicio darinių poveikis saulės elementų elektrinėms charakteristikoms: nuosekliajai varžai, voltamperinių charakteristikų formai. Parodyta, kad pagaminus silicio saulės elemente akytojo silicio sluoksnį, galima veikti (valdyti) saulės elementų voltamperines charakteristikas ir elemento nuosekliąją elektrinę varžą. Nustatyta, kad tiriamajame bandinyje suformavus akytojo silicio sluoksnį, apkrovos voltamperinės charakteristikos užpildos rodiklis padidėjo 1,15 karto, o maksimali elemento kuriama ir apkrovos metu atiduodama elektros energijos galia – 1,19 karto. Tiek pat 1,19 karto padidėjo saulės elemento šviesos konversijos į elektros energiją efektyvumas.

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