Porous Silicon Layer by Electrochemical Etching for Silicon Solar Cell

2007 ◽  
Vol 124-126 ◽  
pp. 987-990 ◽  
Author(s):  
Jeong Kim ◽  
Sang Wook Park ◽  
In Sik Moon ◽  
Moon Jae Lee ◽  
Dae Won Kim

An Electrochemical etching was used to form the porous silicon (PS) layer on the surface of the crystalline silicon wafer. The PS layer, in this study, will act as an antireflection coating to reduce the reflection of the incident light into the solar cell. The etching solution (electrolyte) was prepared by mixing HF (50%) and ethanol which was introduced for efficient bubble elimination on the silicon surface during etching process. The anodization of the silicon surface was performed under a constant current (galvanostat mode of the power supply), and process parameters, such as current density and etching time, were carefully tuned to minimize the surface reflectance of the heavily-doped wafer with sheet resistance between 20-30 / .

2011 ◽  
Vol 2011 ◽  
pp. 1-4 ◽  
Author(s):  
Hyukyong Kwon ◽  
Jaedoo Lee ◽  
Minjeong Kim ◽  
Soohong Lee

Solar cell is device that directly converts the energy of solar radiation to electrical energy. So it is important for solar cell to reduce the surface reflection of light in order to improve the efficiency of the device. Texturing and antireflection coating have been used to reduce the reflection of light. Texturing technology has reduced the 10% of incident light. However, there are a few disadvantages of random pyramid texturing that the results are not always reproducible in an industrial environment. And AR coating (MgF2, ZnS) is difficult to apply the standard industrial process because high vacuum is needed and the expense is very heavy. This paper investigates the formation of a thin film of porous silicon on the surface of crystalline silicon substrate without other AR coating layers. The formation of the porous silicon layer was measured with SEM (scanning electron microscopy). The formation of porous silicon layers on the textured silicon wafer resulted in lower than 5% of reflectance in the wavelength region from 400 to 1000 nm.


2017 ◽  
Vol 46 ◽  
pp. 45-56 ◽  
Author(s):  
Khalid Omar ◽  
Khaldun A. Salman

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.


2013 ◽  
Vol 667 ◽  
pp. 397-401
Author(s):  
S.F.M. Yusop ◽  
N. Azaman ◽  
Hartini Ahmad Rafaie ◽  
S. Amizam ◽  
Saifollah Abdullah ◽  
...  

The characterized on porous silicon layer by using photoluminescence (PL) and I-V measurement (I-V) has been done. Porous silicon was formed by electrochemical etching on (100) p-type Si wafer substrate with the constant current density (20mA/cm2) and variable the etching time. The samples ware prepared under various etching time and properties of porous silicon depend on an etching time. Porous silicon has been used in humidity sensors to detect humidity through changes of its electrical properties. The samples of porous silicon were characterized by using Photoluminescence Spectroscopy (PL) that used to characterize optical properties while I-V Measurement (I-V) used to characterize porous silicon junction properties using a linear voltage source. The result shows PL intensity is increase while the wavelength is decrease for etching time of PSi is longer. For the I-V measurement result shows the etching time affect the resistance of sample due to its porosity.


Author(s):  
Hasan A. Hadi ◽  
Raid A. Ismail ◽  
Nadir F. Habubi

Porous silicon (PS) has been fabricated by Photo-electrochemical etching. Porous silicon was anodized on n-type Si in light using a current density of 20 mA/cm2 for 10 min. The porous structure formation was confirmed using XRD and AFM studies. The root mean square (RMS) roughness of the Porous silicon layer is found to be around 47.5 nm and the ten point height was 317 nm. The average of pores diameter was 419.98nm, and the grain growth is columnar with a (211) preferred orientation. The grain size of the PS was estimated from the Scherer’s formula and found to be 73 nm. All the properties of the porous silicon layer, such as porosity and the thickness depend on the anodization parameters. The porosity (P) was approximately 77%. The thickness of the layer formed during an anodization in constant current was 3.54 nm in gravimetric method, while its value was 1.77 nm by using the theoretical relation.


1999 ◽  
Vol 14 (11) ◽  
pp. 4167-4175 ◽  
Author(s):  
S. Zangooie ◽  
R. Jansson ◽  
H. Arwin

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.


Author(s):  
Hasan A Hadi

In this paper, the structural properties of porous silicon layer PSL were reported. Photo-assisted (laser) electrochemical etching PECE technique used to fabrication PSL from n-type wafer silicon as a function of etching time. Optical microscopy OM image is confirmed that the surface topography of porous silicon layer formation was a mud-like structure. The porosity and thickness have been determined gravimetrically are varied from 61% to 82% and 7.2 µm to 9.4µm respectively. The XRD patterns show that one diffraction peak for all PSL through anodization duration and it is assigned to the (400) plane and data confirmed the porous silicon PS was nanocrystalline.


2021 ◽  
Vol 19 (50) ◽  
pp. 77-83
Author(s):  
Ghasaq Ali Tomaa ◽  
Alaa Jabbar Ghazai

Using photo electrochemical etching technique (PEC), porous silicon (PS) layers were produced on n-type silicon (Si) wafers to generate porous silicon for n-type with an orientation of (111) The results of etching time were investigated at: (5,10,15 min). X-ray diffraction experiments revealed differences between the surface of the sample sheet and the synthesized porous silicon. The largest crystal size is (30 nm) and the lowest crystal size is (28.6 nm) The analysis of Atomic Force Microscopy (AFM) and Field Emission Scanning Electron Microscope (FESEM) were used to research the morphology of porous silicon layer. As etching time increased, AFM findings showed that root mean square (RMS) of roughness and porous silicon grain size decreased and FESEM showed a homogeneous pattern and verified the formation of uniform porous silicon.


2017 ◽  
Vol 24 (Supp01) ◽  
pp. 1850012 ◽  
Author(s):  
IBRAHIM R. AGOOL ◽  
AHMED N. ABD ◽  
MOHAMMED O. DAWOOD ◽  
HARITH M. ABD AL-AMEER ◽  
NADIR F. HABUBI ◽  
...  

The present work is concerned with the preparation of thin films of nanocrystalline porous silicon (PSi) by the method of electrochemical etching. CdTe nanoparticles (NPs) have been prepared by utilizing the pulsed laser ablation in liquid. The measurements of tunneling microscopy, X-ray diffraction (XRD), Fourier transformation infrared spectroscopy (FTIR) and atomic force microscopy (AFE) were carried out and revealed that the PSi was nanostructured and the produced CdTe NPs were ball shaped, having good disposability. The diffusion of CdTe NPs on the properties of PSi solar cell assures that there was an improvement upon their properties. The relationship between [Formula: see text] and the reverse bias voltage was observed to be linear. Values of the built-in potential were observed to be dependent on the laser fluence, current density and the etching time.


2009 ◽  
Vol 609 ◽  
pp. 179-182 ◽  
Author(s):  
Kahina Ait-Hamouda ◽  
A. Ababou ◽  
N. Gabouze

In this work, we report on the results of using a Diamond-Like Carbon / Porous Silicon (DLC/PS) double layer as antireflection coating to enhance the performance of multicrystalline silicon photovoltaic cells. DLC layers were obtained by Plasma Enhanced Chemical Vapor Deposition (PECVD) method. The properties of these layers were investigated in order to establish the optimum preparation conditions for solar cell applications. Then, thin films of combined porous silicon-DLC structure were fabricated for antireflection coating use. The spectral response of a solar cell based on multicrystalline silicon (mc-Si) coated with a PS layer, formed by electrochemical process was enhanced compared to a cell without porous silicon layer as emitter. Further improvements are obtained by a deposition of a thin DLC film. The results of the solar cell parameters before and after porous silicon formation and DLC coating are discussed.


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