2. Articole
Permanent URI for this collectionhttps://msuir.usm.md/handle/123456789/47
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Item COMPOSITION, STRUCTURE, AND WEAR RESISTANCE OF SURFACE NANOSTRUCTURES OBTAINED BY ELECTRIC SPARK ALLOYING OF 65G STEEL(2024) Yurchenco, E.; Ghilețchii, Gheorghe; Vatavu, Sergiu; Petrenco, Vladimir; Harea, Diana; Bubulincă, C.; Dikusar, AlexandrA combination of X-ray diffraction and X-ray fluorescence analysis has shown that the strength- ened layer formed during electric spark alloying of 65G steel with a processing electrode made of the T15K6 hard alloy is a nanocrystalline material, the ratio of the crystalline and amorphous phases in which is achieved by changing the discharge energy. Since an increase in discharge energy leads to an increase in surface rough- ness and its amorphization, there is an optimal value of discharge energy at which maximum wear resistance of the resulting nanocomposites is achieved. At E = 0.2 J, the wear resistance of the hardened layer is 7– 10 times higher than the wear resistance of the untreated surface.Item THE STRUCTURE POLYMER/AS-SE-S DOPED BY BI FOR X-RAY IMAGING(2023) Kiritsa, Arcady; Huștuc, Alexandru; Nasedchina, Nadejda; Vatavu, SergiuThe polymer/67at %(As 2S 3) 0,985 (Bi2Se3) 0,015:33 at.% As 2Se3 structure for X-ray imaging has been investigated. The possibility of registering relief-phase images for radiation of “white” spectrum of tungsten anode X-ray tube was shown.Item PHOTOLUMINESCENCE STUDIES OF THE INTERFACE OF CdS/CdTe HETEROJUNCTIONS(2009) Vatavu, Sergiu; Zhao, Hehong; Caraman, Iuliana; Gașin, Petru; Morel, Don; Ferekides, ChrisThe photoluminescence analysis of CdS/CdTe interface layer of CdS/CdTe heterojunction has been carried out in the 15- 100 K temperature range. An attempt to correlate observed PL features with the CdSxTe1–x layer presence at the interface of the heterojunctions was made. It is assumed the 1.525 eV band has an excitonic origin and 1.37X PL band is a characteristic impurity band due to CdSTe layer. Comparative plots showing SnO2/CdTe PL spectra are given as well.Item СHALCOGENIDE GLASSY SEMICONDUCTORS OF THE SYSTEM AS-SE-S DOPED BY TE FOR X-RAY IMAGING(2022) Kiritsa, Arcady; Spoială, Dorin; Vatavu, SergiuThe polymer/ As-Se-S-Te structure for X-ray imaging has been investigated. The possibility of registering relief-phase images for radiation of “white” spectrum and λ=0,154 nm of Cu anode X-ray tube was shown.Item KINETICS OF PHOTOCONDUCTIVITY AND PHOTOLUMINESCENCE OF CdS/CdTe HETEROJUNCTIONS(2005) Vatavu, Sergiu; Caraman, Iuliana; Gashin, Peter A.The photoluminescence and absoption spectral distribution close to the edge of fundamental band were studied in the CdS and CdTe films components of the CdS/CdTe heterojunctions. Recombination level energetic position was determined. The annealing of the CdS/CdTe heterojunctions in presence of CdCl2 results in formation of new recombination levels, revealed by a luminescent band in the energy range of 1.6-1.7 eV and by the shift of the impurity band maximum to the red wavelength region by 50 meV.Item OXYGEN-DEPENDENT FORMATION OF VO2 THIN FILMS BY METALORGANIC AEROSOL DEPOSITION(Universitatea Tehnică din Moldova, 2018-05-24) Belenchuk, Alexandr; Shapoval, Oleg M.; Zasavitsky, E.; Vatavu, Sergiu; Kiritsa, Arcady; Moshnyaga, V.We report on the growth and properties of vanadium dioxide (VO2) on amorphous and oriented substrates by the low-cost and industry-oriented method of metalorganic aerosol deposition (MAD). X-ray diffraction and temperature- dependent Raman spectroscopy confirm formation of single phase tin films. Abrupt change of resistance by 5×103 times and steep drop of infrared transmission from 49 to 10% at 1700 nm pave the way for application of MAD technique in fabrication of VO2-based optoelectronic and thermochromic devices, such as “smart windows”.Item PARTICULARITĂȚI STRUCTURALE ALE FILMELOR ZnSnN2(CEP USM, 2024) Ghilețchii, Gheorghe; Narolschi, Igor; Rotaru, Corneliu; Rusu, Marin; Vatavu, SergiuZnSnN2 is composed of common non-toxic elements. It exhibits promising optoelectronic properties for application in photoelectric conversion and electromagnetic radiation detection devices. However, the available data on its physical properties are incomplete or contradictory. In this work, we prepare ZnSnN2 thin films and study in detail their structural properties as functi on of deposition conditions. DC magnetron sputtering was used because it allows the preparation of thin polycrystalline ZnSnN2 films on large areas and it can be easily upscaled. The films were prepared using targets of various atomic [Zn]/[Sn] ratios in nitrogen atmosphere at temperatures ranging from 30 to 300°C. Structural analysis, using Grazing Incidence X-ray Diffraction (GI XRD) and X-ray Reflectivity (XRR), revealed the formation of polycrystalline ZnSnN2 films with a wurtzite crystal structure. The obtained structural parameters were found to be influenced by the substrate temperature and elemental concentration in the target. These findings will be used for optimization of the manufacturing process for desired film characteristics.Item STRUCTURA ȘI MORFOLOGIA STRATURILOR NANOMETRICE DE ZnSnN2 PREPARATE PRIN MAGNETRON SPUTTERING(CEP USM, 2022-11-10) Narolschi, Igor; Ghilețchii, Gheorghe; Cliucanov, Alexandr; Rotaru, Corneliu; Spoială, Dorin; Vatavu, Elmira; Şapoval, Oleg; Belenciuc, Alexandr; Dmitroglo, Liliana; Bercu, Elena; Rusu, Marin; Vatavu, SergiuItem STRATURI SUBȚIRI Ga2S3 PENTRU APLICAȚII ÎN DETECTORI DE RADIAȚII ELECTROMAGNETICE(CEP USM, 2022-11-10) Spoială, Dorin; Ghilețchii, Gheorghe; Vatavu, Elmira; Dmitroglo, Liliana; Şapoval, Oleg; Belenciuc, Alexandr; Rotaru, Corneliu; Narolschi, Igor; Vatavu, SergiuItem METALORGANIC AEROSOL DEPOSITION: THE BUILDING OF OXIDE FILMS(CEP USM, 2022-11-10) Şapoval, Oleg; Belenciuc, Alexandr; Vatavu, Sergiu
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