Browsing by Author "Micli, Valdec"

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    CdS NANOMETRIC LAYERS GROWN ON SnO2 COATED GLASS SUBSTRATES FOR PHOTOVOLTAIC DEVICES
    (2012) Botnariuc, Vasile; Gorceac, Leonid; Coval, Andrei; Chetruș, Petru; Cinic, Boris; Raevschii, Simion; Micli, Valdec
    CdS layer thickness decreases at high substrate temperatures due to the fact that a part of CdCl2/(NH2)2 CS aqueous solution evaporates without reaching the substrate surface. CdS layers deposited at the substrate temperature from 250oC to 450oC are growing with a deficit of sulfur. CdS layers with better stoichiometry were grown in the conditions when in the solutions, used for CdS layers growing, there is an excess of thiourea (CdCl2/ TU =1:2). The high charge carrier concentration of 1020cm-3 in CdS layers grown on glass substrates coated with SnO2 layer is related to Sn doping of the layers from SnO2 layer.
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    STRATURI CdS CRESCUTE PE SUPORTURI DE STICLĂ PRIN METODA PULVERIZĂRII
    (CEP USM, 2012) Botnariuc, Vasile; Gorceac, Leonid; Coval, Andrei; Chetruș, Petru; Cinic, Boris; Raevschi, Simion; Micli, Valdec
    CdS layers were grown from aqueous solutions of cadmium chlorine (CdCl2) and thyourine (NH2)2 CS with the molarity of 0,1 M by pulverization method in the temperature range of (250...450)°C. CdS layers were grown on glass substrates covered with a previously deposited SnO2 layer. The deposited CdS layers morphology, atomic weight and composition were studied biasing a sunning electron microscope (SEM). The morphology, atomic weight and composition of the deposited CdS layers considerably changes with the increase of the deposition temperature. The charge carriers’ concentration and their mobility in CdS layers deposited at different temperatures were measured and estimated.
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    STRATURI SUBŢIRI DE CdS DEPUSE DIN SOLUŢII LICHIDE (BAIE CHIMICĂ)
    (CEP USM, 2011) Botnariuc, Vasilii; Gorceac, Leonid; Coval, Andrei; Raevschi, Simion; Micli, Valdec; Cinic, Boris
    Thin layers of CdS were deposited on InP (100) substrates with a (3...5) arc degrees misorientation relative to (110) using water solutions of CdSO4, (NH4)2SO4, NH4OH, NH4Cl and CS(NH2)2 for synthesis. The morphology, atomic composition, photoluminescence and electrical properties of the deposited layers were investigated. The morphology of the CdS layers is characterized by a granular structure that is not changing under thermic treatment. A band in the energy interval (1,55 – 3,1) eV at 77 K with the maximum at 2,282 eV is observed in the photoluminescence spectra of the thin layers. Under thermic treatment from 200°C to 500°C in hydrogen the concentration of charge carriers is increasing from 2⋅1017 cm-3 to 2⋅1018 cm-3.