Browsing by Author "Bruc, Leonid"

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Luminescent properties of ZnS single crystal annealed in the V th group elements melt [Articol]
(2006) Sobolevscaia, Raisa; Corotcov, Vadim; Bruc, Leonid; Sușchevici, Constantin; Chetruș, Petru
The influence of ZnS single crystal annealing in the media based on V-group elements Bi and Sb on its photoluminescent (PL) properties was studied. The following media: Bi, Sb, Bi+Zn, Sb+Zn, Bi+S, Sb+As and Bi+Al were used for the annealing.Two types of the starting crystals were used: I) low resistivity ZnS; II) high resistivity ZnS. The annealing was carried out in the vacuumed silica ampoules at the temperatures of 1400 K (I) and 1200 K (II) during 100hrs. The obtained results show that ZnS crystals annealing in Bi and Sb melts leads to the analogical reorganization of radiation centers based on the native and impurity defects generated by interphase interaction at ZnS-melt interface. These defects are responsible for the appearance of the green radiation having the feature of intracentred transitions. The high value of green band half-width indicates that it is a superposition of a few bands. These could be a PL bands related to the oxygen presence, the impurity centers of the V group elements and to V S .
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.
Silicon carbide nanolayers as a solar cell constituent [Articol]
(2015) Zakhvalinskii, Vasilii; Pilyk, Evghenii; Goncharov, Igor; Simașchevici, Alexei; Șerban, Dormidont; Bruc, Leonid; Curmei, Nicolai; Rusu, Marin
Thin films of predominantly amorphous n-type SiC were prepared by non-reactive magnetron sputtering in an Ar atmosphere. A previously synthesized SiC was used as a solid-state target. Deposition was carried out on a cold substrate of p-type Si (100) with a resistivity of 2 Vcm. The Raman spectrum shows a dominant band at 982 cm 1 , i.e., in the spectral region characteristic for SiC. It was found that the root mean square roughness varies from about 0.3 nm to 9.0 nm when the film thickness changes from about 2 nm to 56 nm, respectively. Transmission electron microscopy studies showed that SiC thin films consist predominantly of an amorphous phase with inclusions of very fine nanocrystallites. A heterostructure consisting of a p-type Si (100) and a layer of predominantly amorphous n-type SiC was fabricated and studied. The investigation of its electrical and photoelectric properties shows that the entire space charge region is located in Si. This is in addition confirmed by the spectral dependence of the p-Si/n-SiC photosensitivity. The barrier height at the p-Si/n-SiC interface estimated from dark I–V characteristics is of the order of 0.9–1.0 eV. Load I–V characteristics of p-Si/n-SiC-nanolayer solar cells demonstrate under standard AM1.5 illumination conditions a conversion efficiency of 7.22%.
Silicon solar cells based on pSi/nSi3N4 nanolayers [Articol]
(2016) Zakhvalinskii, Vasilii; Pilyk, E.; Goncharov, I.; Simașchevici, Alexey; Șerban, Dormidont; Bruc, Leonid; Curmei, Nicolai; Rusu, Marin; Rodrigez, G.
Thin films of Si 3N4 were prepared by non-reactive magnetron sputtering in an Ar atmosphere. A previously synthesized Si 3N4 was used as a solid-state target. Deposition was carried out on a cold substrate of p-Si (1 0 0) with a resistivity of 2 Ohm cm. The Raman spectrum of the deposited Si 3N 4 layers has been investigated. The position of the maximum in the Raman scattering spectrum of Si3 N4 layers corre sponds to the Si3 N4 compound and the shape of the spectrum is characteristic for the nanocrystalline state of the cubic modification of silicon nitride. The film thickness has been determined from atomic force microscopy measurements. The results of electron diffraction investigations of n-Si3 N4 nanolayers with thicknesses up to 20 nm demonstrates that as-deposited Si 3N4 thin films consist of a mixture of microcrystalline and amorphous phases. Solar cells based on heterostructures consisting of a p-type Si (1 0 0) and n-type Si 3N4 nanolayers were fabricated and studied.
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.
Thin Films of Titanium and Tin Oxides and Semiconductor Structures on Their Basis Obtained by Pyrolytic Pulverization: Preparation, Characterization, and Corrosion Properties [Articol]
(2007) Bersirova, Oxana; Bruc, Leonid; Dicusar, Alexandr; Caraman, Mihail; Sidelinicova, Svetlana; Simașchevici, Alexei; Șerban, Dormidont; Iaponteva, Iu.
Peculiarities of obtaining of tin oxide and titanium oxide layers and semiconductor structures on their basis are described. The X-ray diffraction data show that the SnO2 and TiO 2 layers possess the tetragonal crystal structure (anatase modification for TiO2). The results of analysis of the elemental composition and impedance investigations of the fabricated structures in model chloride–sulfate solutions demonstrate that the oxide/SiO2/Si structures are obtained if Si substrates are used. In the case of InP substrates, the oxide layer at the interface is not detected and the corresponding structure is oxide/InP. The results of investigations of corro- sion show that a substantial shift of the corrosion potential to the anode region is observed in the case of depo- sition of SnO2 and TiO2 oxide layers on Si and InP crystals and fabrication of corresponding semiconductor structures. This demonstrates the possibility of the use of these materials in photoelectrochemical applications.