2. Articole
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Item 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, MarinThin 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%.Item Engineering of Thermal Fluxes in Phonon Mismatched Heterostructures [Articol](American Scientific Publishers, 2009) Nika, Denis; Zincenco, N.D.; Pokatilov, E.P.The authors investigated theoretically the lattice thermal fluxes in planar three-layered heterostructures with inner silicon or germanium layer using the face-centered cubic cell dynamic lattice model. It has been established that the acoustically mismatched claddings significantly influence on the phonon spectra and thermal flux of heterostructures. The claddings with small sound velocity reduce average phonon velocity and decrease thermal flux in the nanostructure. The claddings with high sound velocity have an opposite effect. The predicted effects can be used for the engineering of the thermal properties of acoustically mismatched heterostructures and for the improving of the thermal management and thermoelectric properties of nanodevices.Item Падение фононной теплопроводности в сегментированных Si/Ge нанонитях [Articol](CEP USM, 2015) Исакова, КалинаВыполнены теоретические исследования фононного теплового потока в Si/Ge сегментированных нанонитях .Энергетический спектр фононов был рассчитан в рамках модели молекулярной динамики колебаний решетки “face-centered cubic cell”. Решеточная теплопроводность была рассчитана с помощью транспортного уравнения Больмана . Рост локализации фононов , обусловленный перестройкой энергетического спектра , приводит к существенному падению решеточной теплопроводности в сегментированных нанонитях по сравнению с обычными нанонитями Этот эффект связан с исключением из теплового транспорта захваченных фононных мод.Как следствие ,прогнозируется падение фононного теплового потока в широком диапазоне температур для сегментированных нанонитей . Полученные результаты показывают , что сегментированные нанонити являются перспективными для термоэлектрических применений.