Browsing by Author "Curmei, Nicolai"

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Silicon carbide nanolayers as a solar cell constituent [Articol]
(2015) Zakhvalinskii, Vasilii; Pilyk, Evghenii; Goncharov, Igor; Simașchevici, Alexei; Șerban, Dormidont; Bruc, Leonid; Curmei, Nicolai; Rusu, Marin
Thin films of predominantly amorphous n-type SiC were prepared by non-reactive magnetron sputtering in an Ar atmosphere. A previously synthesized SiC was used as a solid-state target. Deposition was carried out on a cold substrate of p-type Si (100) with a resistivity of 2 Vcm. The Raman spectrum shows a dominant band at 982 cm 1 , i.e., in the spectral region characteristic for SiC. It was found that the root mean square roughness varies from about 0.3 nm to 9.0 nm when the film thickness changes from about 2 nm to 56 nm, respectively. Transmission electron microscopy studies showed that SiC thin films consist predominantly of an amorphous phase with inclusions of very fine nanocrystallites. A heterostructure consisting of a p-type Si (100) and a layer of predominantly amorphous n-type SiC was fabricated and studied. The investigation of its electrical and photoelectric properties shows that the entire space charge region is located in Si. This is in addition confirmed by the spectral dependence of the p-Si/n-SiC photosensitivity. The barrier height at the p-Si/n-SiC interface estimated from dark I–V characteristics is of the order of 0.9–1.0 eV. Load I–V characteristics of p-Si/n-SiC-nanolayer solar cells demonstrate under standard AM1.5 illumination conditions a conversion efficiency of 7.22%.
Silicon solar cells based on pSi/nSi3N4 nanolayers [Articol]
(2016) Zakhvalinskii, Vasilii; Pilyk, E.; Goncharov, I.; Simașchevici, Alexey; Șerban, Dormidont; Bruc, Leonid; Curmei, Nicolai; Rusu, Marin; Rodrigez, G.
Thin films of Si 3N4 were prepared by non-reactive magnetron sputtering in an Ar atmosphere. A previously synthesized Si 3N4 was used as a solid-state target. Deposition was carried out on a cold substrate of p-Si (1 0 0) with a resistivity of 2 Ohm cm. The Raman spectrum of the deposited Si 3N 4 layers has been investigated. The position of the maximum in the Raman scattering spectrum of Si3 N4 layers corre sponds to the Si3 N4 compound and the shape of the spectrum is characteristic for the nanocrystalline state of the cubic modification of silicon nitride. The film thickness has been determined from atomic force microscopy measurements. The results of electron diffraction investigations of n-Si3 N4 nanolayers with thicknesses up to 20 nm demonstrates that as-deposited Si 3N4 thin films consist of a mixture of microcrystalline and amorphous phases. Solar cells based on heterostructures consisting of a p-type Si (1 0 0) and n-type Si 3N4 nanolayers were fabricated and studied.