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Publications (53)
In the present work, the formation of silver and copper nanostructures on highly oriented pyrolytic graphite (HOPG) modified with self-assembled gold nanoparticles (Au NPs) is demonstrated. Surface patterning with nanometer resolution was achieved. Different methods such as field emission scanning electron microscopy (FEGSEM), energy dispersive spe...
Control over the deposition of quantum dots (QDs) on nanostructured semiconductors is very important for the photovoltaic performance of QD sensitized solar cells. The best control is typically achieved using bifunctional molecular linkers, such as mercaptopropionic acid (MPA), to attach the QDs to metal oxides in a specific manner; however some ma...
In this study is reported CdTe deposition by Successive Ionic Layer Adsorption and reaction (SILAR) at room temperature onto ZnO nanowires (NWs). The as-deposited CdTe layer exhibits poor crystalline quality and not well defined optical transition which is probably result of its amorphous nature. The implementation of an annealing step and chemical...
Electrodeposited copper thiocyanate (CuSCN) thin films and nanowires have been investigated by X-ray photoelectron spectroscopy (XPS), Raman, and optical spectroscopy. In addition, atomic force microscopy (AFM) together with scanning and transmission electron microscopy (SEM and TEM) have been employed for structural characterization. The multiple...
A new approach for developing solid-state dye-sensitised solar cells (DSSCs) on glass/ITO and plastic substrates (PEN/ITO) is presented in this manuscript. A two step electrodeposition technique has been employed to realize the ZnO photoelectrodes. First a ZnO thin film is deposited on the ITO substrate and subsequently on this buffer layer 650 nm...
Here, we report for the first time that electrodeposited CuSCN nanowires (NWs) could be successfully used as a new hole transporting layer (HTL) in a conventional polymer solar cell (PSC) with a poly[N-9′-heptadecanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)]:[6,6]-phenyl-C71-butyric acid methyl ester (PCDTBT:PC70BM) ble...
A process for fabricating a charge storage layer comprising metal particles of a memory cell, said layer consisting of an organic layer comprising, on the surface, said metal particles, said process comprising the following steps: (a) a step of grafting, onto a metallic, semiconductor or electrically insulating substrate, an organic layer comprisin...
After the first report describing copper thiocyanate (CuSCN) nanowires (NWs) electrochemical deposition from an aqueous electrolyte at room temperature [1], the present study provides additional information on the effect of complexing agent and pH on their formation. The CuSCN electrodeposition from an aqueous solution is a two-step reaction, where...
It would be very attractive to fabricate (Extremely Thin Absorber) ETA-solar cells using one single technique of deposition such as the electrochemical, as this would facilitate the assembly of the solar cells and reduce cost of production. In the ZnONWs/ CdSe/CuSCN solar cells, the ZnO nanowires (NWs) and the absorber, CdSe, were already made by e...
The development of low-band-gap semiconducting materials for the extremely thin absorber (eta) solar cell using cheap and scalable methods is the main objective of this work. The eta-solar cell is composed of all inorganic materials consisting of an extremely thin layer of absorbing material (1.1 < Eg < 1.8 eV) sandwiched between nanostructured tra...
The polymer solar cells (PSCs) have been developed as a promising low-cost renewable energy. The best PSC is composed of a polymer donor layer and a fullerene acceptor bulk-heterojunction (BHJ) composite sandwiched between a transparent conductive oxide, and a metal electrode. In this manuscript we report on the integration of the electrodeposited...
We report on the photosensitization of electrodeposited ZnO nanowire arrays with CuInS2 (CIS) extremely thin layers prepared by two methods: successive ionic layer adsorption and reaction (SILAR) and electrochemical deposition (ECD). This is the first time that such core (ZnO)/shell (CIS) nanostructures are realized. Using SILAR method, 20 nm thick...
Here for the first time electrochemical deposition of copper thiocyanate (CuSCN) nanowires (NWs) from an aqueous electrolyte at room temperature is reported. The formation of CuSCN in an aqueous solution is a two-step reaction, where in the first step Cu2 + is reduced to Cu+ and in the second step Cu+ chemically precipitates with SCN− to form CuSCN...
The electrochemical deposition of ZnO thin films (2D layers) and nanowires on glass substrates covered with transparent conductive oxide (TCO) was studied with the purpose to use them in nanostructured solar cells. It was shown that the bath temperature and the electrolyte concentration played an important role on the ZnO layer morphology, composit...
In this study we report on the galvanostatic deposition of zinc oxide (ZnO) thin films from an aqueous chloride based solution. The influence of the deposition conditions (bath temperature, supporting electrolyte (KCl) concentration and current density) on the properties of ZnO 2D layers is studied. It has been found that to obtain good quality fil...
The present study is divided in two parts. In the first part, the electrochemical deposition of ZnO 2D layers and nanowires and their photosensitization with extremely thin absorbing layers of CdS, CdTe, CuInS2 (CIS) and Cu2ZnSnS4 (CZTS) is discussed. The photosensitizing semiconductors are prepared by close space sublimation (CSS, used for CdTe de...
The future of energy supply depends on innovative breakthroughs regarding the design of cheap, sustainable and efficient systems for the conversion and storage of renewable energy sources. The production of hydrogen through water splitting seems a promising and appealing solution. We found that a robust nanoparticulate electrocatalytic material, H(...
In this study, we are reporting on the electrochemical deposition of two kinds of semiconducting nanowires (ZnO and CuSCN) on different substrates. ZnO and CuSCN are n- and p-type transparent semiconductors whose electrochemical preparation has some similarity, and it is a combination of two steps: an electrochemical reduction with consecutive chem...
In this study we report on ZnO/CdTe core-shell nanostructures fabrication for extremely thin absorber (Eta)-solar cells. Successive ion layer adsorption and reaction (SILAR) and close space sublimation (CSS) methods were used to sensitize electrodeposited ZnO nanowires by CdS and CdTe. The close morphological investigation showed that CdTe thin lay...
This report describes the electrochemical preparation of dendritic silver films with unusual wetting properties coming from the use of a self-assembled gold nanoparticle (Au NP) template. It shows that the Au NP self-assembled monolayer on the highly ordered pyrolytic graphite (HOPG) surface is responsible for the formation of the dendritic morphol...
In the present work, the formation of silver nano- and mesopourous structures on highly oriented pyrolytic graphite (HOPG)
modified with self-assembled gold nanoparticles (Au NPs) is demonstrated. To illustrate the patterning effect with nanometer
resolution of Au NPs, a comparison between silver electrodeposition on bare HOPG (0001) substrate and...
In this manuscript we are reporting on the electrodeposition of ZnO nanowires on potentiostatically and galvanostatically prepared ZnO 2D layers (called buffer layers) on glass substrates covered with transparent conductive oxide (TCO). It is shown that the buffer layer morphology and thickness could be used as parameters to control the ZnO nanowir...
In this manuscript we report the photosensitization of electrodeposited ZnO nanowire arrays with CdS, CdTe, CuZnS (CZS) and Cu 2ZnSnS 4 (CZTS) extremely thin films prepared by: Successive Ion Layer Absorption and Reaction (SILAR), electrochemical deposition (ECD) and Close Space Sublimation (CSS) methods. The structural and optical properties of th...
This paper describes the formation of Cu nanofilms on a Ru/Ta-coated wafer using electrochemical atomic layer deposition (E-ALD).
The initial steps involved cleaning and oxide removal from the Ru/Ta substrate using ultrahigh vacuum electrochemical system.
Auger spectroscopy was used to follow the relative amounts of oxygen, Ru, and Cu on the wafer:...
As ULSI scales to smaller and smaller dimensions, it has become necessary to form layers of materials only a few nm thick. In addition, trenches are now being incorporated in ULSI formation which require conformal coating and will not be amenable to CMP. Atomic layer deposition (ALD) is being developed to address such issues. ALD is the formation o...
Cleaning is one of the key steps of the integration of self aligned barriers (SAB) in microelectronic devices for 32 nm technology and below. It is hence important to investigate the impact of different cleaning solutions on the metallic components of SAB, mainly in which concerns their surface stability. In this sense, the electrochemical behavior...
A 4-aminothiophenol self-assembled monolayer (see image) is prepared on top of a Au(111) crystal, which is subsequently metallized by a nearly closed Pd overlayer of monoatomic height. Analysis of its structural setup and electronic properties reveals that the monolayer consists of a minimum of two molecular layers, and strong chemical interactions...
The actions of glycolic acid and BTA on copper have been investigated by electrochemical methods. Different concentrations in glycolic acid were investigated: 1%wt, 2%wt, 3%wt and 4%wt. Results show that the cleaning action of glycolic acid results from smooth corrosion of the metal. Copper dissolution increases with glycolic acid concentration due...
Deep UV spectroscopic ellipsometry (SE) is used for structure change observations in thin hafnia (HfO2) layers deposited by p-MOCVD on silicon substrate. The absorption edge Eg and most of the critical point transitions in HfO2 are above 6 eV, which makes the extension to Deep UV SE (5–9 eV) very suitable. The phase mixture changes as function of t...
A novel technique has recently been presented for depositing metal layers onto a SAM. This is demonstrated here for Pd and Pt deposits on a mercaptopyridine (4-PyS) SAM. The SAM-covered Au(111) electrode is immersed into the metal-ion-containing solution without potential control. As a result, metal ions, e.g., Pd(II) (respectively Pt(II)) adsorb o...
Clarifying the nature of interactions between metal electrodes and organic molecules still represent one of the challenging problems in molecular electronics that needs to be solved in order to optimize electron transport through a molecular device. For this purpose, electronic properties at metal-molecule interfaces were studied by combining exper...
In this study we describe details of a new technique that allows to deposit metal on top of a self-assembled monolayer (SAM). Monoatomic high platinum islands were formed on a 4-mercaptopyridine SAM on Au(1 1 1) by first immersing the SAM-covered gold electrode in an aqueous solution of K2PtCl4 without potential control to allow Pt(II) ions to form...
In this study, we report on details of a new technique for depositing metal on top of a self-assembled monolayer (SAM). The experiments were performed with 4,4′-dithiodipyridine (4-PySSPy) SAMs on Au(111) electrodes, which were immersed without potential control into a Pd(II)-containing solution, where Pd(II) adsorbs on the surface by forming a com...
Depositing metal layers onto a self-assembled monolayer (SAM) is achieved using a new technique. Au(III) bearing a 4,4'-dithiodipyridine SAM is immersed into a Pd-II solution without potential control, causing Pd-II to adsorb on the surface by forming a complex with the pyridine species. The Pd-II ions are then electrochemically reduced to Pd-0 (se...
4,4'-Dithiodipyridine (PySSPy) monolayers on Au(111) were investigated by cyclic voltammetry, X-ray photoelectron spectroscopy (XPS) and in situ scanning tunneling microscopy (STM). The studies were performed in solutions of different anions and pHs (0.1 M H2SO4, 0.1 M HClO4, 0.1 and 0.01 M Na2SO4, 0.1 and 0.01 M NaOH). The cyclic current-potential...
In situ scanning tunneling microscopy images of self-assembled monolayers (SAMs) of 4-mercaptopyridine (4-MPy) on Au(111) recorded in neat 0.1 M H2SO4 solutions provided evidence for a potential-induced phase transition over the range 0.40-0.15 V versus saturated calomel electrode. Analysis of the data was consistent with the presence of a (5 x squ...
The adsorption of saccharin on Au(111) single crystal in 0.1 M HClO4 solution has been investigated by cyclic voltammetry and capacitance–potential measurements. From pH measurements, it is concluded that the deprotonated molecules form the adsorbed monolayer. The charge under the peaks and spikes present in the voltammograms is associated with a c...
The relationship M'as studied between the corrosion-electrochemical state of Fe-P and AVFe-P alloys containing different amounts of Fe and the composition of the surface film, which plays a crucial role in the corrosion resistance. The eleclrodeposited amorphous alloys Fe-P, i\'i-Fe29-P!S and i\'i-FeO. 7-P18.7 are not passivaled in 0. h\ H£Of The a...
The aqueous corrosion resistances of Zn and Zn–Sn ( 20 wt% Sn) electrodeposits, passivated by immersion in chromating solution with different ratios of Cr(vi) to activating ions, are compared. The electrochemical behaviour of various chromated and nonchromated coatings were investigated in deaerated 0.5 mol dm–3 Na2SO4/pH 5 solution using a.c. impe...
The changes in the composition and structure of layers formed before and after immersion on Zn-15%Sn coating were determined by XPS and SEM. The testing solution contained 5% NaCl and 0,5 mol/dm 3 Na 2SO 4. The dark yellow chromate layer on Zn-Sn coating contained tin and its oxides, which has improved the corrosion resistance afforded by the layer...
The paper discusses the anodic behaviour of the electrodeposited alloys Zn-15%Sn in comparison with pure Zn coatings in 0.5M Na2SO4 and 5% NaCI. A passive state in 0.5M Na2SO4 medium was registered for the alloy while in 5% NaCI the typical passive state was not observed. The selective dissolution of Zn-Sn coatings in media of 0.5 M Na2SO4, and 5%...
The compositions of three types of passive chromate film on an electrodeposited ZnSn alloy containing 15% Sn were studied both at the surface and at depth by X-ray photoelectron spectroscopy (XPS). Samples of dark yellow chromate films on zinc were used for comparison. The elemental and chemical compositions of chromate films formed on the ZnSn a...
ZnSn alloy coatings containing 10%–20% tin with good appearance were deposited from slightly acidic sulphate electrolytes. The effect of the concentration of tin sulphate and the cathodic current density on the composition and the structure of the alloy deposits was investigated. The partial deposition rates for Zn and Sn from electrolytes contain...
The protective ability of passive chromate films on electrodeposited ZnSn alloys (tin content of up to 20%) was studied using a double-cell electrochemical method according to Paatsch. Samples of the same chromate films on zinc deposits were studied for comparison. Three new compositions of chromating solution for electrodeposited ZnSn(15%) alloy...
