Browsing by Author "Gasin, Petru"

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CRYSTALLINE STRUCTURE AND PHOTOLUMINESCENCE OF GaSe-CdSe NANOCOMPOSITE
(2015) Dmitroglo, Liliana; Evtodiev, Igor; Caraman, Iuliana; Kantser, Valeriu; Untila, Dumitru; Stamate, Marius; Gasin, Petru
A material consisting of CdSe and GaSe crystallites with average dimensions of 34 nm and 30 nm respectively was obtained by heat treatment at 753K and 853K of GaSe single crystal plates in Cd vapors during 24 hours. As a result of Cd atoms interaction with Se atoms CdSe layers are formed both onto outer surface and at interface of layered Se-Ga-Ga-Se packages. CdSe crystallites on the surface grow in the form of plates along C6 crystallographic axis. Photoluminescence spectra of the composite, at 78K and 300K, contain predominant bands from the luminescent emission of GaSe and CdSe components.
KINETICS OF PHOTOCONDUCTIVITY AND PHOTOLUMINESCENCE OF CdS/CdTe HETEROJUNCTIONS
(2005) Vatavu, Sergiu; Caraman, Iuliana; Gasin, Petru
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.
PHOTOLUMINESENCE STUDIES OF CDTE/SNO2 AND CDTE/CDS HETEROJUNCTIONS: THE INFLUENCE OF OXYGEN AND THE CDCL2 HEAT TREATMENT
(Elsevier, 2011) Vatavu, Sergiu; Zhao, Hehong; Caraman, Iuliana; Gasin, Petru; Ferekides, Chris
The influence of oxygen and annealing in the presence of CdCl2 on the photoluminescence (PL) spectra of CdTe, component of SnO2/CdTe heterojunction (HJ), has been studied in a temperature range of 17–100 K. The changes in the photoluminescence spectra were studied as a function of excitation intensity. Analysis of the PL spectra was carried out with considerations of spectra obtained from CdS/CdTe heterojunctions. CdTe side PL (SnO2/CdTe HJ) consisted of 1.450 eV-DA defect band and 1.243 eV band (17 K). Annealing resulted in the disappearance of 1.243 eV band in oxygen containing samples. Interface PL for the unannealed samples consisted of mainly the 1.264 eV and a trace of the defect band. The CdCl2 treatment is responsible for an almost symmetrical 1.416 eV band.
STRUCTURAL AND OPTICAL PROPERTIES OF COMPOSITES CONTAINING A III B VI AND A II B VI SEMICONDUCTORS
(2017) Evtodiev, Igor; Untila, Dumitru; Evtodiev, Silvia; Caraman, Iuliana; Gasin, Petru; Dmitroglo, Liliana; Rotaru, Irina; Kantser, Valeriu
By thermal annealing of InSe, GaSe, and GaTe crystals in Zn vapors at 800, 870, and 1050K, respectively, a material consisting of ZnSe crystallites in both GaSe and InSe and ZnTe in GaTe has been prepared. Structural defects induced by intercalated atoms shield excitonic bonds in primary compounds and form both radiative recombination levels and electron trapping levels localized deep in the band gap of AIIIBVI crystals. The energies of trapping levels have been determined from thermally stimulated luminescence curves.
TECHNOLOGY OF VANADIUM AND ITS OXIDES BASED NANOCOMPOSITE STRUCTURES
(INOE Publishing House, 2014) Prilepov, V.; Gasin, Petru; Chirița, Arcadii; Midoni, V.; Spoiala, Dorin; Ketrush, Petru
The peculiarities of vanadium and its oxides based nanocomposite structures fabrication are brought in this paper. The selected fabrication technological conditions allow creating a V2O5 based dielectric matrix in which conducting clusters are uniformly distributed. Some optical and electrical properties of such structures are presented. It was shown that the obtained layers possess high charge sensitivity.