Browsing by Author "Fedorov, Vladimir"

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Influența grosimii stratului de Cd1-xMnxTe asupra parametrilor fotovoltaici ai heterojoncţiunii CdS/Cd1-xMnxTe [Articol]
(CEP USM, 2017) Suman, Victor; Fedorov, Vladimir; Rusnac, Dumitru
Heterojoncțiunile CdS/Cd1-xMnxTe au fost obținute aplicând metoda de volum cvasiînchis. La studierea proprietăților electrice și fotoelectrice ale acestor structuri s-a constatat că fotosensibilitatea a crescut esențial datorită tratării termice în clorură de cadmiu, iar eficiența celulei solare (CS) este de 10,29%. Aceasta se datorează micșorării recombinării purtătorilor de sarcină la suprafață și particularităților proprietăților electrice și fotoelectrce ale acestor structuri.
The intermediate CdO layer influence on solar energy conversion in CdS/CdTe heterojunctions [Articol]
(CEP USM, 2020) Qassem, Amjad-Al; Gagara, Ludmila; Fedorov, Vladimir; Potlog, Tamara
The investigation of TCO/CdS/CdTe heterojunctions by C-U and C-f measurements: Experiment and modeling [Articol]
(IEEE, 2013) Rotaru, Corneliu; Vatavu, Sergiu; Fedorov, Vladimir; Gașin, Petru; Lux-Steiner, Martha; Ferekides, Chris; Rusu, Marin
The paper presents the analysis of C-U and C-f data obtained in the 1 kHz-10 MHz range for CdS/CdTe heterojunctions prepared by CSS onto (ZnO:Al, ZnO:Al/i-ZnO)/Glass substrates. An attempt to model the physical properties of the heterojunctions is made. A small signal analysis has been carried out to establish the equivalent circuit of device. The unusual capacitance behavior of the ZnO based heterojunction is attributed to presence of the barrier at the back contact.
Obţinerea structurilor n+SnO2/nSi şi cercetarea proprietăţilor acestora [Articol]
(CEP USM, 2007) Bobeico, Eugenia; Bruc, Leonid; Caraman, Mihail; Coval, Andrei; Fedorov, Vladimir; Simaşchevici, Alexei; Şerban, Dormidont; Usatîi, Iurie
By the method of pyrolitic spraying spirit solutions of chlorides of tin and antimony transparent (transmission ~ 85%) and conductive (σ ~ 102 Ohm-1cm-1) layers of SnO2:Sb were obtained. By using these layers izotype SIS structures In/n+SnO2 :Sb/SiO2/nSi/Cu are produced. Their electrophysical properties are studied. The energy diagram of heterostructure n+SnO2:Sb/nSi is constructed and the mechanism of current transition is determined.
Parametrii celulelor solare nITO/pInP obţinute prin metoda pulverizării pirolitice în dependenţă de tratarea lor termică în hidrogen [Articol]
(CEP USM, 2007) Simaşchevici, Alexei; Şerban, Dormidont; Gorceac, Leonid; Bruk, Leonid; Coval, Andrei; Usatîi, Iurie; Fedorov, Vladimir
The main objective of this communication is the investigation of the influence of thermal treatment in H2on the parameters of In/nITO/P2O5/pInP/Ag:Zn solar cells obtained by ITO layers pyrolithic pulverization. The ITO/pInP heterostructures obtaining take place at the temperature of 450ºC. The photoelectric parameters of the solar cell received on InP wafers with concentration p = 3·1017cm-3after the thermal treatment are Voc=0.626 V, Isc = 22.72 mA/cm2, FF = 71%, Eff =10.09%. As a result of these investigations it was shown that the thermal treatment of In/nITO/pInP/Ag:ZnSC in H2at 350oC during 10 min. leads to considerable improvement of their photoelectric parameters.
PHOTOCHROMISM IN SELENE-CONTAINING POLYOXOMETALLATES
(Academia de Ştiinţe a Moldovei, 2006) Gutsul, Tatiana; Zubareva, Vera; Chiriţa, Arcadii; Fedorov, Vladimir
Photochromic materials are investigated in last years intensively in connection with prospect of their application in the means of optical holographic and not holographic treatment of information. The photochemistry of the polyoxometallates has been studied and described recently [1, 2]. Earlier we investigated organic-inorganic compositions on the basis of polyoxometallates (POMs) and poly(vinyl alcohol) (PVA), as media for record of the holograms having high resolving power (1000 line\mm), sensitivity 0,2 J/mm2, but poor contrast. Thus, the search of new organicinorganic compositions is of interest. By means of IR, UV and ESR spectroscopy organic -inorganic compositions obtained on the basis of a polyvinylpyrrolidone (PVP) and [Se2W21O69]4-, [Se2W18Cu3O66]12-, [Se2W19 Mo2O69]4- at the all forms of them were investigated. For all investigated compositions the absorption in range 240 nm is characteristic, for the irradiated form - the maximum of absorption is removed (shifted) in range 580-700 nm. The IR spectra of the investigated compositions show four characteristic bands of polyoxometallates in the range of 700-1000 cm-1: νas (W=O), 960 cm-1; νas (W-Ob-W), 890-870 cm-1; νas(W-Oc-W), 750-720 cm-1; νas (Se-O) 830 cm-1 and characteristic bands of polyvinylpyrrolidone (the bands at about 2933-2852, 1687, 1592-1427, corresponding to νC-H, ν C-C, ν C-O, ν O-H, respectively) and also presence of a new band of absorption at 3447 cm-1, corresponding ν (N-H). Results show that polyoxometallates interact with polyvinylpyrrolidone. The composite films exhibit photochromic properties. When irradiated with UV light, the transparent films change from colorless, green or yellow to blue. The photochromism of the composite is due to charge transfer by reduction of polyoxometallates and oxidation of polyvinylpyrrolidone. The mechanism of interaction of polyoxometallates with a polyvinylpyrrolidone as the following photochemical reaction is offered.figure.
Studiul proprietăţilor electrice şi fotovoltaice ale structurilor ITO-SI în baza siliciului multicristalin [Articol]
(CEP USM, 2009) Simaşchevici, Alexei; Şerban, Dormidont; Bruc, Leonid; Gorceac, Leonid; Coval, Andrei; Fedorov, Vladimir; Usatîi, Iurie
ITO-polycrystalline p-type silicon structures with surface barriers are obtained by pyrolytical spraying of indium andtin chloride solutions and their electrical and photoelectrical properties are studied. The spectral sensibility range, current transport mechanisms and the parameters of the heterostructure under forward and reverse bias are determined. It isshown the possibility of using these heterojunctions in solar radiation conversion.