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1

Functional model for the synthesis of nanostructures of the given quality level

Suchikova Y. O., Kovachov S. S., Shishkin G. O., Pimenov D. O., Lazarenko A. S., Bondarenko V. V., Bogdanov I. T.

Archives of Materials Science and Engineering

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2021

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Vol. 107, nr 2

72--84

EN

Purpose: The aim of this paper is to develop a functional model for the synthesis of nanostructures of the given quality level, which will allow to effectively control the process of nanopatterning on the surface of semiconductors with tunable properties. Design/methodology/approach: The paper uses the IDEF0 methodology, which focuses on the functional design of the system under study and describes all the necessary processes with an accuracy sufficient for an unambiguous modelling of the system's activity. Based on this methodology, we have developed a functional model for the synthesis of nanostructures of the given quality level and tested its effectiveness through practice. Findings: The paper introduces a functional model for the synthesis of nanostructures on the surface of the given quality level semiconductors and identifies the main factors affecting the quality of nanostructures as well as the mechanisms for controlling the formation of porous layers with tunable properties. Using the example of etching single-crystal indium phosphide electrochemically in a hydrochloric acid solution, we demonstrate that the application of the suggested model provides a means of forming nanostructures with tunable properties, assessing the quality level of the nanostructures obtained and bringing the parameters in line with the reference indicators at a qualitatively new level. Research limitations/implications: Functional modelling using the IDEF0 methodology is widely used when process control is required. In this study it has been applied to control the synthesis of nanostructures of the given quality level on the surface of semiconductors. However, these studies require continuation, namely, the establishment of correlations between the technological and resource factors of synthesis and the acquired properties of nanostructures. Practical implications: This study has a significant practical effect. Firstly, it shows that functional modelling can reduce the time required to form large batches of the given quality level nanostructures. This has made it possible to substantiate the choice of the initial semiconductor parameters and nanostructure synthesis modes in industrial production from the theoretical and empirical perspective. Secondly, the presented methodology can be applied to control the synthesis of other nanostructures with desired properties and to reduce the expenses required when resources are depleted and the cost of raw materials is high. Originality/value: This paper is the first to apply the IDEF0 methodology to control the given quality nanostructure synthesis. This paper will be of value to engineers who are engaged in the synthesis of nanostructures, to researchers and scientists as well as to students studying nanotechnology.

2

Justification of the most rational method for the nanostructures synthesis on the semiconductors surface

Suchikova Y., Vambol S., Vambol V., Mozaffari N., Mozaffari N.

Journal of Achievements in Materials and Manufacturing Engineering

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2019

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Vol. 92, nr 1-2

19--28

EN

Purpose: of this paper is to justification the most rational method for the nanostructures synthesis on the semiconductors surface, which is capable of providing high quality synthesized nanostructures at low cost and ease of the process. Design/methodology/approach: The choice of the optimal method of synthesis was carried out using the hierarchy analysis method, which is implemented by decomposing the problem into more simple parts and further processing judgments at each hierarchical level using pair comparisons. Findings: The article describes the main methods of synthesis of nanostructures, presents their advantages and disadvantages. The methods were evaluated by such criteria as: environmental friendliness, efficiency, stages number of the technological process, complexity, resources expenditure and time and effectiveness. Using the hierarchy analysis method, has been established that electrochemical etching is the most important alternative, and when choosing a nanostructures synthesis method on the semiconductors surface, this method should be preferred. Such studies are necessary for industrial serial production of nanostructures and allow reducing expenses at the realization of the problem of synthesis of qualitative samples. Research limitations/implications: In this research, the hierarchy analysis method was used only to select a rational method for synthesizing nanostructures on the semiconductors surface. However, this research needs to be developed with respect to establishing a correlation between the synthesis conditions and the nanostructures acquired properties. Practical implications: First, was been established that the optimal method for the nanostructures synthesis on the semiconductors surface is electrochemical etching, and not lithographic or chemical method. This allowed the theoretical and empirical point of view to justify the choice of the nanostructures synthesis method in the industrial production conditions. Secondly, the presented method can be applied to the synthesis method choice of other nanostructures types, which is necessary in conditions of resources exhaustion and high raw materials cost. Originality/value: In the article, for the first time, the choice of the nanostructures synthesis method on the semiconductors surface is presented using of paired comparisons of criteria and available alternatives. The article will be useful to engineers involved in the nanostructures synthesis, researchers and scientists, as well as students studying in the field of "nanotechnology".

3

Oxide crystals on the surface of porous indium phosphide

Suchikova Y. O., Bogdanov I. T., Kovachov S. S.

Archives of Materials Science and Engineering

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2019

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Vol. 98, nr 2

49--56

EN

Purpose: f this paper is to is to establish the patterns of oxide formation on the surface of indium phosphide during electrochemical etching of mono-InP. Design/methodology/approach: A porous surface was formed with the anode electrolytic etching. Morphology of the surface was studied with the help of scanning electron microscope JSM-6490. The analysis of chemical composition of porous surface of samples was also performed. Findings: It was shown that during the electrochemical etching of indium phosphide, oxide films and crystallites form on the surface. It has been established that crystalline oxides are formed mainly on the surface of n-type indium phosphide. Continuous oxide films are predominantly formed on the surface of p-InP. Research limitations/implications: The research was carried out for indium phosphide samples synthesized in the solution of hydrofluoric acid, though, carrying out of similar experiments for crystalline oxides on the surface of porous indium phosphide obtained in other conditions, is necessary. Practical implications: The study of oxide crystals on the surface of porous indium phosphide has great practical importance since it is the reproducibility of experimental results that is the main problem of modern materials science, the more nanoengineering. Oxides can significantly affect the properties of materials. On the one hand, oxides significantly affect the recombination properties of materials, this can impair the operation of semiconductor devices. On the other hand, oxide films can serve as a passivating coating for the surface of a porous semiconductor. Such an oxide property will be useful for the practical application of nanostructured indium phosphide. Therefore, questions of the conditions for the formation of semiconductor intrinsic oxides, their structure, and chemical composition, and also the effect of oxides on the physical and technical characteristics of materials are important. Originality/value: The patterns of oxide formation on the surface of indium phosphide during electrochemical etching are investigated in this work. It is shown for the first time that the structure of an oxide depends on the orientation of the surface of the semiconductor. It was shown that continuous oxide films are formed on the surface of p-InP, and oxide crystalline clusters are formed on the surface of n-InP.

4

Fabrication and Optoelectronic properties of Fluoride tin oxides/porous silicon/p-Silicon heterojunction

Hadi H. A.

International Letters of Chemistry, Physics and Astronomy

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2014

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Vol. 17, iss. 2

142--152

EN

In this paper, formation of a nanostructure semi transparence fluoride tin oxides (FTO) by spray pyrolysis technique on porous silicon PS layer. Porous silicon PS layer was prepared by anodization of p-type silicon wafers to fabricate of the UV- Visible Fluoride-doped tin oxide /Porous silicon /p-Si heterojunction photodetector. Optical properties of FTO thin films were measured. The optical band gap of 3.77 eV for SnO2 : F for film was deduced. From (I-V) and (C-V) measurements, the barrier ØB height for FTO/PS diode was of 0.77, and the built in voltage Vbi, which was of 0.95 V. External quantum efficiency was 55 % at 500 nm which corresponding to peak responsivity of 1.15 A/W at 1 V bias. The PS band gap in the vicinity of PS/c-Si heterojunction was 1.38 eV.

5

Investigation of electrochemically produced black silicon with silver nanoparticles

Jarimaviciute-Zvalioniene R., Kaminskiene Z., Prosycevas I., Lapinskas S.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 10a

311-313

EN

Black silicon is new material, which first time was produced in 2006, using femtosecondary laser. Using electrochemically performed black silicon we can produce cheaper solar cells with higher efficiency, comparing to monocrystalline and polycrystalline silicon solar cells, what is important economically today. Efficiency of solar cells also can be increased by application of nanoparticles with inherent plasmon resonance properties. Black silicon with precipitated plasmonic nanoparticles (such as silver or gold) can revolutionary change the market of solar cells. In this work the black silicon were prepared electrochemically from n-type (100) silicon wafers at room temperature in HF:H2O:C2H5OH solution by ratio 2:1:1, using ultrasound excitation of 4.4 mW. The silver nanoparticles were precipitated from silver nitrate and sodium citrate colloidal solution. The structures of black silicon and black silicon with silver nanoparticles were investigated by SEM and lower reflection coefficient of samples of black silicon with Ag nanoparticles was detected. The size of Ag nanoparticles has varied from 30 to 70 nm. Presence of silver on silicon surface was detected by SEM-EDX technology.

PL

Czarny krzem jest nowym materiałem, który został wyprodukowany po raz pierwszy w roku 2006 przy użyciu lasera femtosekundowego. Wykorzystując przetworzony elektrochemicznie czarny krzem można wyprodukować tańsze ogniwa słoneczne o wyższej sprawności w porównaniu do ogniw słonecznych z monokrystalicznego i polikrystalicznego krzemu, co jest obecnie ekonomicznie uzasadnione. Sprawność ogniw słonecznych może być również zwiększona poprzez zastosowanie nanocząstek o właściwościach rezonansu plazmowego. Czarny krzem z wytrąconymi nanocząstkami plazmowymi (takimi jak srebro lub złoto) może zmienić w sposób rewolucyjny rynek ogniw słonecznych. W niniejszej pracy czarny krzem przygotowano elektrochemicznie wykorzystując struktury krzemowe typu n (100) w temperaturze pokojowej w roztworze HF:H2O:C2H5OH o proporcjach 2:1:1, wykorzystując pobudzanie ultradźwiękowe o mocy 4,4 mW. Nanocząstki srebra zostały wytrącone z roztworu koloidalnego azotanu srebra i cytrynianu sodu. Struktury czarnego krzemu i czarnego krzemu z nanocząstkami srebra zostały przebadane poprzez SEM, w wyniku czego stwierdzono niższy współczynnik odbicia próbek czarnego krzemu z nanocząstkami Ag. Rozmiar nanocząstek Ag zmieniał się od 30 do 70 nm. Obecność srebra na powierzchni krzemu została stwierdzona za pomocą technologii SEM-EDX. (Badania wytworzonego elektrochemicznie czarnego krzemu z nanocząstkami srebra).

6

Optical characterization of nanoporous GaN Through Electroless Wet Chemical Etching

Chuah L.S., Hassan Z., Abu Hassan H.

Materials Science Poland

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2008

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Vol. 26, No. 3

609--615

EN

High quality unintentionally doped n-type GaN layers were grown on Si(111) substrate, using AlN as the buffer layer, by radio frequency (RF) nitrogen molecular beam epitaxy. The present work reports on the photoluminescence (PL) studies of porous GaN prepared by ultraviolet assisted electrochemical etching in a solution of 2:1:1 HF:CH3OH:H2O2 under illumination of an UV lamp with 500 W power for 10, 25 and 35 min. The optical properties of porous GaN samples were compared to the corresponding asgrown GaN. PL studies suggested that the porosity was capable of improving the lattice mismatch induced strain. Porosity induced PL intensity enhancement was found in nanoporous samples. The resulting nanoporous GaN displays blue-shifted PL spectra compared to the as-grown GaN. Appearance of the blue-shifted emission is correlated with the development of highly anisotropic structures in the morphology.

7

Morphology of silicon (111) during electrochemical etching in NH4F electrolytes

Jakubowicz J.

Advances in Materials Science

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2005

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Vol. 5, nr 1-3

49-54

EN

The n-type silicon with (111) orientation and resistivity of 8-12 .źcm was electrochemically etched. The results obtained by electrochemical etching of silicon in 0.1M NH4F (pH4.5), 0.1M NH4F (pH4.0) and 0.2M NH4F (pH4.0) electrolytes, indicates that slight increase of the NH4F concentration by 0.1M results in faster silicon dissolution. In slightly reactive 0.1M NH4F (pH4.5), we can observe initial stage of silicon dissolution on the inside edges of atomic terraces. Flat atomic terrace under electrochemical etching undergoes to mesa-type structures surrounded by strongly corrugated areas. The diameter and heights of the mesas are 150-200 nm and 5-7 nm, respectively. The mesa-type structures are the remnants of the atomic terraces and theirs formation proceed independently on the electrolyte concentration. The mesas appear faster at higher concentration and faster disappear by pits formation. During increase of etching time, increase of pore size, more in the case of diameter than depth, because pits coagulation appears.