Browsing by Author "Suman, Victor"

Filter results by typing the first few letters
Now showing 1 - 5 of 5
  • Thumbnail Image
    Item
    CARACTERIZAREA STRUCTURALĂ A STRATURILOR SUBȚIRI DE Sb2Te3 FABRICATE PRIN METODA SUBLIMĂRII ÎN VOLUM CUAZI-ÎNCHIS
    (CEP USM, 2024) Untila, Dumitru; Lungu, Ion; Suman, Victor; Gadiac, Ivan; Potlog, Tamara
    Straturi subțiri de Sb2Te3 au fost obținute pe suporturi de sticlă ITO/CdS prin metoda sublimării în volum cuazi-închis (CSS). Prin analiza difracției razelor X, s-a constatat că straturile subțiri de Sb2Te3 au rețea cristalină hexagonală, ce aparține grupului spațial P6/mmm. Creșterea temperaturii evaporatorului de la 470°C până la 530°C, duce la modificarea orientării preferabile de creștere a cristalitelor compusului Sb2Te3 și la creșterea gradului de cristalinitate a acestuia. Investigațiile Raman, au confirmat rezultatele XRD și au fost folosite pentru a obține informații suplimentare asupra structurii straturilor subțiri de Sb2Te3. Caracteristica dubletului observat la 119,54 cm–1 și 138,83 cm–1, precum și la 93,65 cm-1 si 107,36 cm-1 cu intensitate integrală foarte mică pot fi atribuite interacțiunii Te-Te între pachetele de telurură de antimoniu.
  • Thumbnail Image
    Item
    CHEMICAL METHOD FOR THE GALLIUM ARSENIDE RECTIFICATION STRUCTURE DIVIDE INTO CRYSTALS
    (UTM, 2009-10-01) Baranov, Simion; Cinic, Boris; Dudca, Tudor; Suman, Victor
    This investigations are referred to power semiconductor devices (PSD) area manufactured by gallium arsenide (GaAs) advanced technology. The work’s objective is excluding the break-down effect on the p-n junction surface of high voltage devices, which is advance progressed with diminishing the crystal dimensions in the dividing process of the semiconductor structures. We propose the method of the GaAs deep etching by a mixture utilizing concentrated acids as nitric and hydrochloric acids in equal rates. After 30 min of mixing up the solution formation is consorted of the endothermic reaction, bound up by nitrosyl chloride (NOCl) formation, which dissolves the GaAs decomposed product in solution by arsenic oxidation up to As(V), forming ortoarsenic acid and gallium chloride. This method is used for dividing semiconductor structure of GaAs with 0.4-0.6 mm of thickness in small dimensioned crystals. The advantages of this technology are the great speed of GaAs dissolving, low costs of manufacturing and profitableness.
  • Thumbnail Image
    Item
    ELECTRICAL AND PHOTOELECTRICAL PROPERTIES OF HETEROJUNCTIONS ON THE BASE OF Cu(InGa)Se2
    (2005) Chetruș, Petru; Gașin, Petru; Nicorici, Valentina; Suman, Victor
    CdS films deposited by hot wall technique on mica were used as substrates for Cu(InGa)Se2 deposition. Two methods were used for the deposition of Cu(InGa)Se2 films: a) vacuum thermal evaporation from a single source and b) “flash” evaporation. The obtained films were of p-type conductivity with hole concentration varied from 2×1018 cm-3 to 6×1020 cm-3 depending on the fabrication method. The structures Cu(InGa)Se2–CdS were divided into two groups: the structures of type I having the CdS film thickness from 1.6 m to 2.8 m and the structures of type II having the CdS film thickness from 0.6 m to 0.8 m. It was established that the direct/reverse current ratio is 8-16. For the first type heterostructures the diffusion potential is 1.2–1.8 V and for the second type is 0.2–0.34 V. The Cu(InGa)Se2–CdS fotosensitivity is situated in the wavelength region from 0.51 m to 1.1 m and is determined by the electron-hole pair generation in both materials.
  • Thumbnail Image
    Item
    INFLUENȚA GROSIMII STRATULUI DE Cd1-xMnxTe ASUPRA PARAMETRILOR FOTOVOLTAICI AI HETEROJONCŢIUNII CdS/Cd1-xMnxTe
    (CEP USM, 2017) Suman, Victor; Fedorov, Vladimir; Rusnac, Dumitru
    Heterojoncțiunile CdS/Cd1-xMnxTe au fost obținute aplicând metoda de volum cvasiînchis. La studierea proprietăților electrice și fotoelectrice ale acestor structuri s-a constatat că fotosensibilitatea a crescut esențial datorită tratării termice în clorură de cadmiu, iar eficiența celulei solare (CS) este de 10,29%. Aceasta se datorează micșorării recombinării purtătorilor de sarcină la suprafață și particularităților proprietăților electrice și fotoelectrce ale acestor structuri.
  • Thumbnail Image
    Item
    STUDY OF THE EFFECT OF HEAT TREATMENT ON OPTICAL AND ELECTRICAL PARAMETERS OF CuO FILMS
    (2024) Suman, Victor; Lungu, Igor; Potlog, Tamara; Ghimpu, Lidia