Facultatea de Fizică şi Inginerie / Faculty of Physics and Engineering

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Author: search.filters.author.Potlog, TamaraEnd date: 2020

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    Effect of chlorine doping on CdTe thin films [Articol]
    (2013) Dumitriu, Petru; Potlog, Tamara; Mîrzac, Alexandra; Dmitroglo, Liliana; Luca, Dumitru
    This paper analyzes the effect of chlorine treatment on the structure and resistance of CdTe layers. The morphology, chemical composition, and structure were studied using scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and X-ray diffraction (XRD). Both non-activated and activated CdTe layers are polycrystalline with an average grain size being three times higher after chlorine activation and thermal treatment. All CdTe thin layers regardless of the treatment temperature have a cubic crystal structure.
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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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    Synthesis and properties of Al-doped ZnO thin films for photovoltaics [Articol]
    (Institute of Electrical and Electronics Engineers Inc., 2018-11-27) Potlog, Tamara; Lungu, Ion; Botnariuc, Vasile; Gorceac, Leonid; Raevschi, Simion; Taku, Miyake; Worasawat, Suchada; Mimura, Hidenori
    Polycrystalline undoped and Al-doped ZnO thin films were deposited by spray pyrolysis using oxygen and argon atmospheres. The influence of postdeposition vacuum annealing on the structure, morphology and optical properties was studied by X-ray diffraction, atomic force microscopy and UV–VIS spectroscopy. The thermal vacuum annealing induces structural and morphological changes, especially in Al-doped ZnO thin films synthetized in oxygen atmosphere. Further on, the electrical conductivity in dependence of the nature of gas atmosphere and Al concentration is discussed.
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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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    Effect of carrier gas and vacuum annealing on the physical properties of ZnO thin films doped with gallium by chemical spray pyrolysis [Articol]
    (Editura "Tehnica-UTM", 2018-05-24) Potlog, Tamara; Lungu, Ion; Botnariuc, Vasile; Raevschi, Simion; Worasawat, Suchada; Mimura, Hidenori; Gorceac, Leonid
    Structural, optical and electrical properties of zinc oxide thin films doped with 2% Ga, annealed in the vacuum at the same temperature and obtained onto glass substrates by the chemical spray pyrolysis method in the different gas atmospheres were investigated by X-ray Diffraction (XRD), UV-VIS spectrophotometry and Hall measurements, respectively. XRD studies revealed that all films were polycrystalline in nature, with a hexagonal wurtzite crystal structure and a predominant (002) c-axis orientation. All ZnO:Ga thin films had higher than 80 % transmittances in the visible region. Doping with 2% Ga led to a decrease in the optical band gap indifferent of the nature of the carrier gas. The synthesis of ZnO thin films with 2% Ga doping and annealing in the same conditions in Ar and O2 atmospheres led to the lower conductivity with electron concentration of 1016 cm−3.
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    Fabricarea structurilor SnO2/CdTe/ZnO şi cercetarea proprietăţilor acestora [Articol]
    (CEP USM, 2020) Lungu, Ion; Colibaba, Gleb; Potlog, Tamara
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    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
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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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    Electrical properties of thermal annealed in vacuum spray deposited al-doped zno thin films [Articol]
    (Springer Nature, 2020) Potlog, Tamara; Lungu, Ion; Raevschi, Simion; Botnariuc, Vasile; Robu, Stephan; Worasawat, Suchada; Mimura, Hidenori
    Al-doped ZnO thin films have been prepared by spray pyrolysis, which facilitates the incorporation of a higher percentage of dopant atoms. The vacuum thermally annealed at 420 °C temperature thin films have been characterized by X-ray diffraction (XRD), optical spectroscopy. Electrical conductivity and the Hall effect are investigated in the temperature interval (77–300) K. X-ray analysis results reveal that all the films are polycrystalline with a hexagonal wurtzite structure with a preferential orientation according to the direction (002) plane. Different characters of the temperature dependence of conductibility are observed in the Al-doped ZnO films vacuum thermally annealed at 420 °C temperature. In all cases, the conductivity, mobility carriers and carriers’ concentration of ZnO thin films obtained under Ar are higher than under O2 atmosphere, unless they are not doped. of your paper no longer than 300 words.