STRUCTURAL AND PHOTOLUMINESCENCE PROPERTIES OF POROUS SILICON: EFFECT OF HF CONCENTRATION

2006 ◽  
Vol 13 (04) ◽  
pp. 351-356 ◽  
Author(s):  
B. NATARAJAN ◽  
V. RAMAKRISHNAN ◽  
V. VASU ◽  
S. RAMAMURTHY
Keyword(s):  
Porous Silicon ◽  
Chemical Species ◽  
Silicon Layer ◽  
Spectral Shift ◽  
Porous Silicon Layer ◽  
Atomic Force ◽  
Prepared Material ◽  
Alloy Effect ◽  
To Come ◽  
P Type

Structural and Photoluminescence (PL) studies are carried out for p-type porous silicon materials prepared with different Hydrogen Fluoride (HF) concentration. Surface morphology of porous silicon was analyzed using atomic force microscope (AFM). Fourier Transform Infra Red (FTIR) spectra indicate that surface of porous silicon contain chemical species like SiH n. PL studies reveal that there is a prominent emission peak around 625 nm. No spectral shift is observed. It is further observed that the emission intensity increases with HF concentration. The PL of the porous silicon layer was found to come from its upper part, which was confirmed by a simulation of the PL spectrum employing an optical model. The refractive indices of the porous silicon layer were also determined through this simulation. The large hydrogen concentration in freshly prepared material has led to the suggestion that a silicon–hydrogen alloy effect is responsible for the luminescence.

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).

scholarly journals Morphology and FT IR spectra of porous silicon

2017 ◽  
Vol 68 (7) ◽  
pp. 53-57 ◽  
Author(s):  
Martin Kopani ◽  
Milan Mikula ◽  
Daniel Kosnac ◽  
Jan Gregus ◽  
Emil Pincik
Keyword(s):  
Porous Silicon ◽  
Ir Spectra ◽  
Silicon Layer ◽  
Porous Silicon Layer ◽  
Layer Formation ◽  
Porous Si ◽  
Ft Ir ◽  
P Type ◽  
Type Sample ◽  
Ftir Investigation

AbstractThe morphology and chemical bods of p-type and n-type porous Si was compared. The surface of n-type sample is smooth, homogenous without any features. The surface of p-type sample reveals micrometer-sized islands. FTIR investigation reveals various distribution of SiOxHycomplexes in both p-and n-type samples. From the conditions leading to porous silicon layer formation (the presence of holes) we suggest both SiOxHyand SiFxHycomplexes in the layer.

Formation of Porous Silicon Nanostructures in NH4F/C3H8O3 Solution

2015 ◽  
Vol 1131 ◽  
pp. 25-34
Author(s):  
Chanika Puridetvorakul ◽  
Chalongwut Boonpratum ◽  
Wandee Onreabroy ◽  
Tula Jutarosaga
Keyword(s):  
Porous Silicon ◽  
High Surface ◽  
Silicon Layer ◽  
Average Diameter ◽  
Porous Silicon Layer ◽  
Silicon Nanostructures ◽  
Porous Structures ◽  
Using Data ◽  
P Type ◽  
Anodization Method

Nanostructured porous silicon layer were successfully formed by an anodization method in viscous electrolyte containing glycerol and NH4F solution. P-type (100) silicon wafers were anodized with various anodizing times (1-8 h), NH4F concentrations (0.5-3 M) and applied voltages (10-30 V). The current density characteristic during anodizing and the morphology of porous silicon were measured using data acquisition loggers and field emission electron microscope (FE-SEM), respectively. The anodized surface produced high surface roughness and showed two types of porous structures consisting of macropores (macro-PSi) and mesopores (meso-PSi). The meso-Psi located in the macro-PSi structures. The size of macro-PSi increased with the increase of anodization time, the decrease of NH4F concentration and the decrease of applied voltage. The average diameter and depth of macro-PSi varied from 0.34 to 1.40 μm and 54 to 446 nm, respectively. For the meso-PSi, this method can produce an average diameter and thickness of mesopores in the range of 19-33 nm and 52-157 nm, respectively.

A Systematic Study of the Structural and Luminescence Properties of P-Type Porous Silicon

1995 ◽  
Vol 378 ◽  
Author(s):  
H. Yoon ◽  
M. S. Goorsky
Keyword(s):  
Porous Silicon ◽  
Current Density ◽  
Storage Time ◽  
Silicon Layer ◽  
Porous Silicon Layer ◽  
Luminescence Properties ◽  
Strained Layers ◽  
X Ray ◽  
P Type ◽  
The Relationship

AbstractThe structural and luminescence properties of (001) p-type porous silicon samples (p∼0.1-0.2 Ω•cm) fabricated electrochemically under various conditions were investigated using high resolution double and triple axis diffraction and photoluminescence spectroscopy. We show the sensitivity of the structure of the porous silicon to the current density in the range of 10-50 mA/cm2, HF acid concentration in the range of 15% - 30%, and the evolution of the structure with time. We have found a systematic dependence of the amount of strain in the porous silicon layer (PSL) on the current density. The effect of the HF concentration is such that at 25% and 30% HF, PSLs are formed which are crystalline and strained, but at a lower HF concentration (15%), strained layers are not formed. The perpendicular strain in the layer increases linearly with storage time but the in-plane lattice constant of the porous silicon remains matched to the substrate. Further, we utilized x-ray reciprocal space maps to observe that, with storage time, there is an increase in the diffuse scattering from the PSL due to an increase in the range of tilts in the layer. Room temperature photoluminescence emission was observed for all 15% and 25% HF samples, but not for all 30% HF samples. Higher peak luminescence energy was obtained with lower HF concentration. Finally, we note the relationship between the strain in the PSL and the luminescence properties.

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.

On the Origin of the Electrically-Induced Spectral Shift of Porous Silicon Photo- and Electro- Luminescence

1994 ◽  
Vol 358 ◽  
Author(s):  
A. Bsiesy ◽  
M.A. Hory ◽  
F. Gaspard ◽  
R. Herino ◽  
M. Ligeon ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Voltage Drop ◽  
Silicon Layer ◽  
Blue Shift ◽  
Spectral Shift ◽  
Porous Silicon Layer ◽  
Carrier Injection ◽  
External Bias ◽  
Voltage Drops ◽  
Silicon Nanocrystallites

ABSTRACTExperimental results showing two electrically-induced phenomena, namely the voltage-tunable electroluminescence (VTEL) and the voltage-induced quenching of porous silicon photoluminescence(QPL) are given. In both cases, a spectral shift as large as 300 nm can be recorded for an external bias variation of only 0.5V. This spectral shift is characterised by a blue-shift of the whole EL line in the case of the VTEL whereas it results from a progressive and selective quenching starting by the low-energy part of the luminescence line in the case of the QPL experiments. The origin of this spectral shift is discussed in relation with an electrically-induced selective carrier injection into the silicon nanocrystallites accompanied with an enhancement of the non-radiative recombination which might take place by an Auger relaxation process. Finally, it is shown that a partial oxidation of the porous silicon layer leads to a complete loss of the selectivity of these two phenomena. This result is qualitatively discussed by considering the voltage drop distribution between the substrate and the silicon nanocrystallites. The voltage drops are modified by the growth of the oxide layer on the nanocrystallite surface leading to a modification of the energy barriers at the crystallite boundaries.

Formation of a Low Reflective Surface on Silicon Solar Cells by Chemical Treatment Using Ag-Assisted Electroless Etching

2012 ◽  
Vol 512-515 ◽  
pp. 43-46
Author(s):  
Guo Feng Ma ◽  
Hong Ling Zhang ◽  
Xue Fei Yang
Keyword(s):  
Porous Silicon ◽  
Room Temperature ◽  
Silicon Layer ◽  
Porous Silicon Layer ◽  
Silicon Solar Cells ◽  
Mixed Solution ◽  
Etching Solution ◽  
Electroless Etching ◽  
Ag Particle ◽  
P Type

The Ag-assisted electroless etching of p-type silicon substrate in HF/H2O2solution at room temperature was investigated. The porous silicon layer was formed in a mixed solution of H2O2and HF by using screen-printed Ag front electrodes as the catalyst. And influence of the different concentration etching solution (HF and AgNO3) on the porous silicon layer was study by scanning electron microscopy (SEM). Through investigation of the track of catalyst particles, it was shown that Ag really catalyses the etching of silicon underneath Ag particle.

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.

Microstructure of pores in N+-silicon layers

1987 ◽  
Vol 45 ◽  
pp. 252-253
Author(s):  
V. S. Kaushik
Keyword(s):  
Porous Silicon ◽  
Hydrofluoric Acid ◽  
Silicon Layer ◽  
Porous Silicon Layer ◽  
Silicon On Insulator ◽  
Cross Sectional ◽  
Porous Layers ◽  
Doped Silicon ◽  
Oxidized Porous Silicon ◽  
P Type

Oxidized porous silicon has drawn considerable interest as one of the alternatives for implementing silicon-on-insulator technology. Buried porous layers can be formed by utilizing the preferential pore formation in highly doped silicon during anodic etching in hydrofluoric acid. This porous silicon layer (PSL) can be subsequently oxidized rapidly at low temperatures to yield a device-quality silicon island layer, which is dielectrically isolated from the substrate. Although pores can be formed in both n-type and p-type silicon, the latter has received more attention. This paper presents the results of cross-sectional TEM (XTEM) observations of the microstructure of pores in n+ silicon.Samples used in this study were n- /n+/n- doped silicon (001) wafers which had been anodically etched in a hydrofluoric acid solution to form the PSL in the n+ layer via trenches etched through the n- surface layer.

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