Facultatea de Fizică şi Inginerie / Faculty of Physics and Engineering

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Author: search.filters.author.Maticiuc, Natalia

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    Electrical properties of thermally annealed CdS thin films obtained by chemical bath deposition [Articol]
    (Institute of Electrical and Electronics Engineers Inc., 2011-10-17) Scorțescu, Dumitru; Maticiuc, Natalia; Nicorici, Valentina; Spalatu, Nicolae; Potlog, Tamara; Hiie, Jaan; Valdna, Vello
    Electrical conductivity and the Hall-effect are investigated in the temperature interval (80-400) K on thermally annealed in H 2 CdS thin films obtained by chemical bath deposition. Different characters of the temperature dependence of conductibility are observed in the CdS films annealed at different temperatures. The Hall measurements allow calculating the values of the NA , N D , n ex and ED . According to Hall measurements the CdS films show several donor levels at different energetic depths in dependence of the annealing temperature. The sample annealed at high temperatures than 350oC proves to be compensated with a sharply decreasing electrical conductivity with the temperature decrease.
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    The caracterization of the CdS-based solar cell heterojunctions [Articol]
    (Institute of Electrical and Electronics Engineers Inc., 2010-10-11) Potlog, Tamara; Botnariuc, Vasile; Gorceac, Leonid; Spalatu, Nicolae; Maticiuc, Natalia; Raevschi, Simion
    The CdS-based solar cell heterojunctions (HJ) have been obtained by growth of CdS at relatively lower temperature using the close space sublimation method(CSS). Investigation of the photovoltaic characteristics shows an efficiency of about 12 % for InP/CdS and 9.6 % for CdS/CdTe solar cell HJ. The analysis of the forward dark current-voltage and the capacitance-voltage characteristics indicate a tunnelling recombination current which flows through states near or at the interfaces of a thermal energy of about 0.62 eV for CdS/CdTe and 0.42 eV for InP/CdS solar cell heterojunctions. The solar energy conversion efficiency is influenced by the interface states through the open circuit voltage and the fill factor.
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    Characterization of photovoltaic devices based on CdTe [Articol]
    (CEP USM, 2014) Dumitriu, Petru; Maticiuc, Natalia; Potlog, Tamara
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    Caracterizarea heterostructurilor CdS/CdTe/Te cu ajutorul caracteristicilor capacitate-tensiune [Articol]
    (CEP USM, 2009) Potlog, Tamara; Spalatu, Nicolae; Maticiuc, Natalia
    Thin Film CdS/CdTe heterojunctions were fabricated by close space sublimation at the substrate temperature 340 ± 5ºC and evaporator temperature 610oC± 5ºC. Capacitance-voltage characteristics in the region of temperatures 313 K – 363 K were measured. Was established that the capacitance of heterojunction CdS/CdTe/Te increases from 658 (cm2/pF)2, T=313 K to 1096 (cm2/pF)2, T=393 K. The width space charge region at room temperature is 7,4 μm, but at the tempera-ture of 393 K are 0,15 μm. In the above mentioned temperature region the potential contact barrier height decreases from 0,8 V at room temperature (293 K) up to 0,12 V at the temperature of 393K. The ionized-charge concentration profi le (NA-ND)is not constant, but it is increasing together with the enlarging of the depth of heterojunction and measure tem-perature, indicating to a high density of the states in the space charge region