Metal-Assisted Chemical Etching of Multicrystalline Silicon in HF/ Na2S2O8 Produces Porous Silicon

2005 ◽  
Vol 480-481 ◽  
pp. 139-144 ◽  
Author(s):  
T. Hadjersi ◽  
N. Gabouze ◽  
A. Ababou ◽  
M. Boumaour ◽  
W. Chergui ◽  
...  

A new metal-assisted chemical etching method using Na2S2O8 as an oxidant is proposed to form a porous layer on a multicrystalline silicon (mc-Si). This method does not need an external bias and enables formation of uniform porous silicon layers, more rapidly than the conventional stain etching method. A thin layer of Pd is deposited on the mc-Si surface prior to immersion in a solution of HF and Na2S2O8. The characterisations of etched layer formed by this method as a function of etching time were investigated by scanning electron microscopy, X-ray diffraction (XRD), Energy-dispersive X-ray (EDX) and reflectance spectroscopy. It shows that the surface is porous and the etching is independent of grain orientation. In addition, reflectance measurements made with a variety of etching conditions show a lowering of the reflectance from 25 % to 6 % measured with respect to the bare as-cut substrate. However, this result can be improved by changing the experimental conditions (concentration, time, temperature, …).

ISRN Optics ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Igor Iatsunskyi ◽  
Valentin Smyntyna ◽  
Nykolai Pavlenko ◽  
Olga Sviridova

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.


2014 ◽  
Vol 924 ◽  
pp. 166-169 ◽  
Author(s):  
Pan Pan Yue ◽  
Yong Zhong Jin ◽  
Xu Dong Hu ◽  
Hong Yang Yan ◽  
Guo Qing Zeng

Ni-P ultra-black films having conical pores with the diameter of ~ 10-30 μm and the depth of ~ 15-30 μm were prepared by chemical etching of electroless plated Ni-P films using 8 mol/L nitric acid at 40 °C for 60 s. The phase composition and microstructure of the film samples were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The results show that the diameter and depth of the etching pores become larger and the flat top regions bounded by etching pores become smaller by the coalescence of adjacent pores with the increase of etching time. The surface morphologies of the etched Ni-P films are characterized by the distribution of conical pores.


Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2518
Author(s):  
Dorota Kołodyńska ◽  
Yongming Ju ◽  
Małgorzata Franus ◽  
Wojciech Franus

The possibility of application of chitosan-modified zeolite as sorbent for Cu(II), Zn(II), Mn(II), and Fe(III) ions and their mixtures in the presence of N-(1,2-dicarboxyethyl)-D,L-aspartic acid, IDHA) under different experimental conditions were investigated. Chitosan-modified zeolite belongs to the group of biodegradable complexing agents used in fertilizer production. NaP1CS as a carrier forms a barrier to the spontaneous release of the fertilizer into soil. The obtained materials were characterized by Fourier transform infrared spectroscopy (FTIR); surface area determination (ASAP); scanning electron microscopy (SEM-EDS); X-ray fluorescence (XRF); X-ray diffraction (XRD); and carbon, hydrogen, and nitrogen (CHN), as well as thermogravimetric (TGA) methods. The concentrations of Cu(II), Zn(II), Mn(II), and Fe(III) complexes with IDHA varied from 5–20 mg/dm3 for Cu(II), 10–40 mg/dm3 for Fe(III), 20–80 mg/dm3 for Mn(II), and 10–40 mg/dm3 for Zn(II), respectively; pH value (3–6), time (1–120 min), and temperature (293–333 K) on the sorption efficiency were tested. The Langmuir, Freundlich, Dubinin–Radushkevich, and Temkin adsorption models were applied to describe experimental data. The pH 5 proved to be appropriate for adsorption. The pseudo-second order and Langmuir models were consistent with the experimental data. The thermodynamic parameters indicate that adsorption is spontaneous and endothermic. The highest desorption percentage was achieved using the HCl solution, therefore, proving that method can be used to design slow-release fertilizers.


1994 ◽  
Vol 342 ◽  
Author(s):  
I. BÁrsony ◽  
J.G.E. Klappe ◽  
É. Vázsonyi ◽  
T. Lohner ◽  
M. Fried

ABSTRACTChemical and mechanical stability of porous silicon layers (PSL) is the prerequisite of any active (luminescent) or passive (e.g. porous substrate) integrated applications. In this work X-ray diffraction (XRD) was used to analyze quantitatively the strain distribution obtained in different morphology PSL that were prepared on (100) p and p+Si substrates. Tetragonal lattice constant distortion can be as high as 1.4% in highly porous “as-prepared” samples. Incoherent optical heating RTO is governed by the absorption in the oxidized specimen. PSL show vertical inhomogeneity according to interpretation of spectroscopic ellipsometry (SE) data. Oxygen incorporation during RTO is controlled by specific surface (in p+ proportional, in p inversely proportional with porosity), while the developing compressive stress depends on pore size, and decreases with porosity in both morphologies.


2013 ◽  
Author(s):  
Igor Iatsunskyi ◽  
Valentyn Smyntyna ◽  
Mykolai Pavlenko ◽  
Olga Kanevska ◽  
Yuliia Kirik ◽  
...  

2009 ◽  
Vol 63 (6) ◽  
Author(s):  
Yan Li ◽  
Chuan-Sheng Liu ◽  
Yun-Ling Zou

AbstractZnO nano-tubes (ZNTs) have been successfully synthesized via a simple hydrothermal-etching method, and characterized by X-ray diffraction, field emission scanning electron microscopy and room temperature photoluminescence measurement. The as-synthesized ZNTs have a diameter of 500 nm, wall thickness of 20–30 nm, and length of 5 µm. Intensity of the plane (0002) diffraction peak, compared with that of plane (10$$ \bar 1 $$0) of ZNTs, is obviously lower than that of ZnO nano-rods. This phenomenon can be caused by the smaller cross section of plane (0002) of the nano-tubes compared with that of other morphologies. On basis of the morphological analysis, the formation process of nano-tubes can be proposed in two stages: hydrothermal growth and reaction etching process.


1996 ◽  
Vol 276 (1-2) ◽  
pp. 1-6 ◽  
Author(s):  
Daniel Bellet ◽  
Gérard Dolino

2018 ◽  
Vol 7 (3.11) ◽  
pp. 48
Author(s):  
Kevin Alvin Eswar ◽  
Mohd Husairi Fadzillah Suhaimi ◽  
Muliyadi Guliling ◽  
Zuraida Khusaimi ◽  
Mohamad Rusop ◽  
...  

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). 


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