Facultatea de Fizică şi Inginerie / Faculty of Physics and Engineering
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Item Crystallinity and optical properties of β-Ga2O3/Ga2S3 layered structure obtained by thermal annealing of Ga2S3 semiconductor [Articol](2021) Sprincean, Veaceslav; Lupan, Oleg; Caraman, Iuliana; Untila, Dumitru; Postica, Vasile; Cojocaru, Ala; Gapeeva, Anna; Palachi, Leonid; Adeling, Rainer; Tiginyanu, Ion; Caraman, MihailIn this work, the β-Ga2O3 nanostructures were obtained by thermal annealing in air of β-Ga2S3 single crystals at relatively high temperatures of 970 K, 1070 K and 1170 K for 6 h. The structural, morphological, chemical and optical properties of β-Ga2O3–β-Ga2S3 layered composites grown at different temperatures were investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) as well as photoluminescence spectroscopy (PL) and Raman spectroscopy. The results show that the properties of obtained β-Ga2O3–β-Ga2S3 composites were strongly influenced by the thermal annealing tem- perature. The XRD and Raman analyses confirmed the high crystalline quality of the formed β-Ga2O3 nano- structures. The absorption edge of the oxide is due to direct optical transitions. The optical bandwidth was estimated to be approximately 4.34-4.41 eV, depending on the annealing temperature. Annealing of the β-Ga2S3 monocrystals at a higher temperature of 1170 K showed the complete conversion of the surface to β-Ga2O3. These results demonstrate the possibility to grow high quality β-Ga2O3–β-Ga2S3 layered composites and β-Ga2O3 nanostructures in large quantities for various applications such as gas sensing, non-toxic biomedical imaging, nonlinear optical, as well as power device applications. Micro and nanocrystallites present on the surface of the Ga2O3 layer contribute to a diffusion of the incident light which leads to an increase of the absorption rate allowing thus to reduce the thickness of the Ga2O3 layer, in which the generation of unbalanced charge carriers takes place. By decreasing the Ga2O3 layer thickness in such layered composites, the efficiency of photovoltaic cells based on such junctions can be increased.Item Caracterizarea structurală a nanoformațiunilor de Ga2O3 obținute prin tratament termic al monocristalelor Ga2O3 [Articol](Universitatea Tehnică din Moldova, 2018-05-24) Untilă, Dumitru; Sprincean, Veaceslav; Caraman, Mihail; Cojocaru, Ala; Lupan, Oleg; Tighineanu, Ion; Palachi, Leonid; Caraman, IulianaPrin tratament termic (TT), în atmosferă normală, al monocristalelor β-Ga2S3, cu rețea cristalină monoclinică, la temperaturi din intervalul 970-1170 K, timp de 3-6 ore, suprafața acestora se acoperă cu un strat omogen de β-Ga2O3, cu rețea cristalină monoclinică. La interfața monocristal-oxid se formează nanocristalite de Ga2O3 și Ga2S3. Structura cristalină și dimensiunile medii ale cristalitelor sunt analizate prin măsurări XRD, SEM și Raman.Item Educaţie pentru Drone. Suport de curs(CEP USM, 2019) Nedeoglo, Natalia; Rotaru, Corneliu; Sprincean, Veaceslav; Danici, Anton; Seinic, Valeriu; Vozian, Constantin; Cazan, Valeriu; Corcimari, Ion; Cebotaru, EugeniaItem Procese de generare-recombinare a purtătorilor de sarcină de neechilibru în compozitul Ga2O3/Ga2Se3 și în structurile microlamelare - Ga2O3/GaSe [Articol](CEP USM, 2020) Sprincean, Veaceslav; Dmitroglo, Liliana; Vatavu-Cuculescu, Elmira; Caraman, MihailItem Monitorizarea proceselor de dezvoltare a plantelor prin măsurări ale spectrelor optice [Articol](CEP USM, 2020) Sprincean, Veaceslav; Caraman, Mihail; Chiriţa, Arcadii; Paladi, FlorentinItem Cercetarea spectrelor de reflectanța a microobiectelor biologice la distanța [Articol](CEP USM, 2020) Chiriţa, Arcadii; Caraman, Mihail; Sprincean, Veaceslav; Paladi, FlorentinItem Porous InP as piezoelectric component in magneto-electric composite sensors [Articol](io, 2011) Gerngross, M.-D.; Sprincean, Veaceslav; Leisner, M.; Carstensen, J.; Föll, H.; Tiginyanu, IonWe report on the fabrication of cheap piezoelectric porous InP templates by electrochemical etching and additional purely chemical post-etching and on the galvanic filling of the resulting nanopore array with Ni-Fe using a highly viscous electrolyte. The d14 component of porous InP is found to be around a stunning |60| pm/V. The deposited Ni-Fe shows a very narrow hysteresis loop with low coercive field strength (170 G) and very low remanence (0.005 emu).Item UAV-based measuring station for monitoring and computational modeling of environmental factors [Articol](IEEE, 2021) Sprincean, Veaceslav; Paladi, Adrian; Andruh, Vasili; Danic, Anton; Lozovanu, Petru; Paladi, FlorentinSoftware application for computational modeling of environmental factors, in connection with UAV -based measuring station for environmental factors monitoring in realtime regime precise measurements [1], which facilitates the analysis and interpretation of the monitoring results, has been developed as an integrated mobile system for exact monitoring and computational modeling of environmental factors. This paper deals with the second stage related to the drone-dedicated system developed at the Moldova State University (MSU) in the research laboratory Environmental Physics and Modeling Complex Systems (MSU ePhysMCS Lab) for the observation and support of the air analysis for pollution, chemical and radiological contaminations [2]. The exact data are used in modeling of the impact of biotic and abiotic factors during the real-time environmental monitoring process.Item The structure and chemical composition of Ga2O3 oxide prepared by annealing of Ga2Se3 crystals [Articol](Springer Nature, 2020) Sprincean, Veaceslav; Vatavu, Elmira; Dmitroglo, Liliana; Untila, Dumitru; Caraman, Iuliana; Caraman, MihailThe chemical composition and structure of Ga2O3 obtained by thermal treatment (TT) in air of β-Ga2Se3 crystals were studied using the X-ray diffraction (XRD) method, Raman spectroscopy, EDX, and SEM. The surface of the Ga2Se3 crystal air annealed at 770 K is covered by β-Ga2O3 layer of microcrystallites and as well as by β-Ga2Se3 crystallites. The oxygen is non-homogeniously distributed on the surface of the 770 K annealed sample. The sample obtained by TT at 1150 K consists of nanolamella, nanotowers, and nanobars of β-Ga2O3, their size being estimated to 10–200 nm.Item UVS in monitoring of environmental factors [Articol](IEEE, 2020) Sprincean, Veaceslav; Paladi, Adrian; Bulimaga, Tatiana; Paladi, FlorentinAdvanced physical technologies developed in the research laboratories of the Moldova State University (MSU) are used in the monitoring of environmental factors with the application of UVS (Unmanned Vehicle Systems). The aim of this research is development of an integrated mobile system for the exact monitoring and computational modeling of environmental factors. This paper deals with the first advisable stage related to a drone-dedicated system for the observation and support of the air analysis for pollution, chemical and radiological contaminations. The exact data can then be used in modeling of the impact of biotic and abiotic factors during the real-time environmental monitoring process