EFFECT OF ETCHING TIME ON OPTICAL AND MORPHOLOGICAL FEATURES OF N-TYPE POROUS SILICON PREPARED BY PHOTO-ELECTROCHEMICAL METHOD

2016 ◽  
Vol 78 (3) ◽  
Author(s):  
Asad A. Thahe ◽  
Noriah Bidin ◽  
Mohammed A. Al-Azawi ◽  
Naser M. Ahmed
Keyword(s):  
Porous Silicon ◽  
Gravimetric Method ◽  
Constant Current ◽  
Etching Time ◽  
Absorption Data ◽  
Time Duration ◽  
Constant Current Density ◽  
Force Microscopy ◽  
Atomic Force ◽  
Structure Properties

Achieving efficient visible photoluminescence from porous-silicon (PSi) is demanding for optoelectronic and solar cells applications. Improving the absorption and emission features of PSi is challenging. Photo-electro-chemical etching assisted formation of PSi layers on n-type (111) silicon (Si) wafers is reported. Samples are prepared at constant current density (~30 mA/cm2) under varying etching times of 10, 15, 20, 25, and 30 min. The influence of etching time duration on the growth morphology and spectral properties are inspected. Room temperature photoluminescence (PL) measurement is performed to determine the optical properties of as-synthesized samples. Sample morphologies are imaged via Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The thickness and porosity of the prepared samples are estimated using the gravimetric method. The emission and absorption data is further used to determine the samples band gap and electronic structure properties. Results and analyzed, interpreted with different mechanisms and compared.  

scholarly journals Morphology and luminescence of photo-electrochemically synthesized porous silicon: Influence of varying current density

2017 ◽  
Vol 13 (4) ◽  
pp. 708-710
Author(s):  
Asad Thahe ◽  
Hazri Bakhtiar ◽  
Noriah Bidin ◽  
Zainuriah Hassan ◽  
Zainal Abidin Talib ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Current Density ◽  
Room Temperature ◽  
Gravimetric Method ◽  
Etching Time ◽  
Time Duration ◽  
High Quality ◽  
Force Microscopy ◽  
Room Temperature Photoluminescence ◽  
Atomic Force

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. 

scholarly journals Peculiarities of Photoluminescence in Porous Silicon Prepared by Metal-Assisted Chemical Etching

ISRN Optics ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Igor Iatsunskyi ◽  
Valentin Smyntyna ◽  
Nykolai Pavlenko ◽  
Olga Sviridova
Keyword(s):  
Porous Silicon ◽  
Chemical Etching ◽  
Etching Time ◽  
Force Microscopy ◽  
Porous Layers ◽  
Atomic Force ◽  
Silicon Nanostructure ◽  
Metal Assisted Chemical Etching ◽  
Concentrated Solution ◽  
P Type

Photoluminescent (PL) porous layers were formed on p-type silicon by a metal-assisted chemical etching method using H2O2 as an oxidizing agent. Silver particles were deposited on the (100) Si surface prior to immersion in a solution of HF and H2O2. The morphology of the porous silicon (PS) layer formed by this method was investigated by atomic force microscopy (AFM). Depending on the metal-assisted chemical etching conditions, the macro- or microporous structures could be formed. Luminescence from metal-assisted chemically etched layers was measured. It was found that the PL intensity increases with increasing etching time. This behaviour is attributed to increase of the density of the silicon nanostructure. It was found the shift of PL peak to a green region with increasing of deposition time can be attributed to the change in porous morphology. Finally, the PL spectra of samples formed by high concentrated solution of AgNO3 showed two narrow peaks of emission at 520 and 550 nm. These peaks can be attributed to formation of AgF and AgF2 on a silicon surface.

scholarly journals The Effect of Etching Time On Structural Properties of Porous Quaternary AlInGaN Thin Films

2021 ◽  
Vol 19 (50) ◽  
pp. 77-83
Author(s):  
Ghasaq Ali Tomaa ◽  
Alaa Jabbar Ghazai
Keyword(s):  
Porous Silicon ◽  
Crystal Size ◽  
Electrochemical Etching ◽  
Silicon Layer ◽  
Porous Silicon Layer ◽  
Etching Time ◽  
Etching Technique ◽  
Force Microscopy ◽  
Atomic Force ◽  
Homogeneous Pattern

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.

Effect of Etching Time on Electrical and Optical Properties of Porous Silicon

2013 ◽  
Vol 667 ◽  
pp. 397-401
Author(s):  
S.F.M. Yusop ◽  
N. Azaman ◽  
Hartini Ahmad Rafaie ◽  
S. Amizam ◽  
Saifollah Abdullah ◽  
...  
Keyword(s):  
Optical Properties ◽  
Porous Silicon ◽  
Electrochemical Etching ◽  
Silicon Layer ◽  
Porous Silicon Layer ◽  
Constant Current ◽  
Voltage Source ◽  
Etching Time ◽  
Constant Current Density ◽  
Wafer Substrate

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.

IMPROVING THE PHOTORESPONSE OF POROUS SILICON FOR SOLAR CELL APPLICATIONS BY EMBEDDING OF CdTe NANOPARTICLES

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 ◽  
...  
Keyword(s):  
Solar Cell ◽  
Porous Silicon ◽  
Electrochemical Etching ◽  
Etching Time ◽  
Reverse Bias Voltage ◽  
Tunneling Microscopy ◽  
Laser Ablation In Liquid ◽  
Force Microscopy ◽  
Cdte Nanoparticles ◽  
Atomic Force

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.

STUDY OF POROUS SILICON SURFACE PROPERTIES

1996 ◽  
Vol 03 (02) ◽  
pp. 1235-1239
Author(s):  
K. W. CHEAH ◽  
T. Y. LEUNG ◽  
M. H. CHAN ◽  
S. K. SO
Keyword(s):  
Porous Silicon ◽  
Surface States ◽  
Silicon Layer ◽  
Structural Difference ◽  
Porous Silicon Layer ◽  
Etching Time ◽  
Free Standing ◽  
Force Microscopy ◽  
Photothermal Deflection Spectroscopy ◽  
Atomic Force

Porous silicon is a material with a coral-like structure which has a fractal surface. To study these aspects of porous silicon and its relationship with the luminescence property, we have used atomic force microscopy (AFM). Samples were prepared using either pure HF or HF diluted with ethanol. From the results of AFM, distinct structural difference was observed from samples prepared by these two etchants. If we relate the structures to their respective photoluminescence spectra, it appears that finer structure produced shorter wavelength peak photoluminescence. However, the columns of the samples were too large for one to attribute the luminescence to quantum confinement only. Hence, an alternative model may be required to explain the luminescence mechanism. We have also observed that the composition of the etchant can also affect the evolution of the fractal dimension with respect to etching time. Probing of the surfcace electron states was performed using photothermal deflection spectroscopy (PDS). In order to ensure that only porous silicon layer was probed, free-standing films of various porosity were produced for the PDS measurement. The probe energy range was from 0.56 eV to 2.5 eV so that both the bulk states and the surface states were probed. The results showed that there is a clear blueshift of the energy band gap with respect to porosity, and the absorption coefficient decreases with porosity increase at a fixed photon energy. Overtones of hydrides and fluorides of silicon were also observed.

scholarly journals Effect of SnS Thin Film on the Performance of Porous Silicon Photodiode

2016 ◽  
Vol 63 ◽  
pp. 67-76 ◽  
Author(s):  
Ahmed N. Abd ◽  
Wasna'a M. Abdulridha ◽  
Mohammed Odda Dawood
Keyword(s):  
Thin Film ◽  
Porous Silicon ◽  
Silicon Layer ◽  
Porous Silicon Layer ◽  
Etching Time ◽  
X Ray Diffraction ◽  
Silicon Photodiode ◽  
Force Microscopy ◽  
Atomic Force ◽  
Evaporation Technique

In this study, Al/SnS/PS/n-Si/Al photodiode was fabricated and investigated. SnS thin film were prepared by thermal evaporation technique on porous silicon layer which prepared by anodization technique at 32mA/cm2 etching current density and etching time 15min.The characteristics of porous silicon and SnS were investigated by using x-ray diffraction XRD, atomic force microscopy AFM, Fourier transformation infrared spectroscopy FT-IR.Dark and illuminated current-voltage I-V characteristics, spectral responsivity, specific detectivity of photodiode were investigated after depositing. Significant improvement in photosensitivity and detectivity of porous silicon photodiode after SnS deposition on porous silicon was noticed.

Effect of current density on the porous silicon preparation as gas sensors**

2021 ◽  
Vol 30 (1) ◽  
pp. 257-264
Author(s):  
Muna H. Kareem ◽  
Adi M. Abdul Hussein ◽  
Haitham Talib Hussein
Keyword(s):  
Porous Silicon ◽  
Gas Sensors ◽  
Current Density ◽  
Room Temperature ◽  
Low Cost ◽  
High Surface ◽  
Volume Ratio ◽  
Etching Time ◽  
Force Microscopy ◽  
Materials Used

Abstract In this study, porous silicon (PSi) was used to manufacture gas sensors for acetone and ethanol. Samples of PSi were successfully prepared by photoelectrochemical etching and applied as an acetone and ethanol gas sensor at room temperature at various current densities J= 12, 24 and 30 mA/cm2 with an etching time of 10 min and hydrofluoric acid concentration of 40%. Well-ordered n-type PSi (100) was carefully studied for its chemical composition, surface structure and bond configuration of the surface via X-ray diffraction, atomic force microscopy, Fourier transform infrared spectroscopy and photoluminescence tests. Results showed that the best sensitivity of PSi was to acetone gas than to ethanol under the same conditions at an etching current density of 30 mA/cm2, reaching about 2.413 at a concentration of 500 parts per million. The PSi layers served as low-cost and high-quality acetone gas sensors. Thus, PSi can be used to replace expensive materials used in gas sensors that function at low temperatures, including room temperature. The material has an exceptionally high surface-to-volume ratio (increasing surface area) and demonstrates ease of fabrication and compatibility with manufacturing processes of silicon microelectronics.

Influence of Etching Time on Surface Structural Properties of p- and n- Type Porous Silicon Nanostructures by Photo-Electrochemical Anodic Etching

2012 ◽  
Vol 576 ◽  
pp. 511-515
Author(s):  
N.A. Asli ◽  
Maslihan Ain Zubaidah ◽  
S.F.M. Yusop ◽  
Khairunnadim Ahmad Sekak ◽  
Mohammad Rusop ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Crystalline Silicon ◽  
Surface Characteristic ◽  
Electrochemical Anodization ◽  
Silicon Nanostructures ◽  
Etching Time ◽  
Force Microscopy ◽  
Etching Parameters ◽  
P Type ◽  
Substrate Doping

Porous silicon nanostructures (PSiN) are nanoporous materials which consist of uniform network of interconnected pore. The structure of PSiN is depending on etching parameters, including current density, HF electrolyte concentration, substrate doping type and level. In this work, the results of a structural p-type and n-type of porous silicon nanostructures were investigated by Field Emission Scanning Electron Microscopy (FESEM) and Atomic Force Microscopy (AFM) is reported. Samples were prepared by photo-electrochemical anodization of p- and n-type crystalline silicon in HF electrolyte at different etching time. The surface morphology of PSiN was studied by FESEM with same magnification shown n-type surface form crack faster than p-type of PSiN. While the topography and roughness of PSiN was characterize by AFM. From topography shown the different etching time for both type PSiN produce different porosity and roughness respectively. There is good agreement between p- and n-type have different in terms of surface characteristic.

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