silicon matrix
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2021 ◽  
Vol 12 (4) ◽  
pp. 306-313
Author(s):  
S. I. Pokutnyi ◽  
◽  
N. G. Shkoda ◽  

It is shown that electron tunneling through a potential barrier that separates two quantum dots of germanium leads to the splitting of electron states localized over spherical interfaces (a quantum dot – a silicon matrix). The dependence of the splitting values of the electron levels on the parameters of the nanosystem (the radius a quantum dot germanium, as well as the distance D between the surfaces of the quantum dots) is obtained. It has been shown that the splitting of electron levels in the QD chain of germanium causes the appearance of a zone of localized electron states, which is located in the bandgap of silicon matrix. It has been found that the motion of a charge-transport exciton along a chain of quantum dots of germanium causes an increase in photoconductivity in the nanosystem. It is shown that in the QD chain of germanium a zone of localized electron states arises, which is located in the bandgap of the silicon matrix. Such a zone of local electron states is caused by the splitting of electron levels in the QD chain of germanium. Moreover, the motion of an electron in the zone of localized electron states causes an increase in photoconductivity in the nanosystem. The effect of increasing photoconductivity can make a significant contribution in the process of converting the energy of the optical range in photosynthesizing nanosystems. It has been found that comparison of the splitting dependence of the exciton level Eех(а) at a certain radius a QD with the experimental value of the width of the zone of localized electron states arising in the QD chain of germanium, allows us to obtain the distances D between the QD surfaces. It has been shown that by changing the parameters of Ge/Si heterostructures with germanium QDs (radius of a germanium QD, as well as the distance D between the surfaces of the QDs), it is possible to vary the positions and widths of the zones of localized electronic states. The latter circumstance opens up new possibilities in the use of such nanoheterostructures as new structural materials for the creation of new nano-optoelectronics and nano-photosynthesizing devices of the infrared range.


2021 ◽  
Vol 0 (9) ◽  
pp. 2-7
Author(s):  
E. A. Kosenko ◽  
◽  
V. A. Nelyub ◽  

Properties of polymer composite material consisting of carbon fabric and two matrix types (epoxy and organic-silicon) have been studied. The main purpose of the organic-silicon matrix is to relax stresses arising in carbon-filled plastic components under loads and to decelerate (or stop) crack growth. The structure of the composite material was determined by using a tomography. On the basis of the structure, a finite-element model was developed and a calculation of the stressed-deformed state depending on elastic characteristics of the matrix was performed. A safety factor calculation was made. It was found out that the addition of organic-silicon material in the composite composition made possible to decrease stress values in the crack tip that considerably increased the service life of such materials.


2021 ◽  
Author(s):  
Priyatha Premnath

Currently fabricated bio-matrices lack important characteristics such as nanometer scale, ‘bumpy’ morphology and an interlinked structure. Therefore, cells cultured on such matrices may not truly represent phenotypes of cells grown in the natural environment. This thesis deals with the synthesis of a three dimensional nanofibrous silicon matrix that is interlinked and possesses a ‘bumpy’ structure that mimics the natural extra cellular matrix. This silicon matrix can be tailored to suit applications of cell proliferation and manipulation. Cell-biomaterial studies show that osteoblasts and fibroblasts proliferated by 300% on three dimensional nanofibrous matrix compared to virgin silicon. To induce controlled cell proliferation, the addition of gold to the silicon matrix was perceived. The phase of gold was altered and combined with silicon forming a unique hybrid structure that prevented the growth of cells in areas of increased gold concentration. Increased gold concentration indicated lower adhesion forces and reduced zeta potentials which consequently lead to decreased cell growth. In addition, the interaction of cancer cells with the three dimensional silicon and gold-silicon hybrid nanofibrous network was studied. Results indicate a 96% reduction in cancer cells compared to virgin silicon. The reduction in cells is attributed to- different phases of silicon and silicon oxides in nanoparticle form, the encapsulation of cells by the nanofibers and apoptosis of cells owing to nanoparticles entering cells passively. To control the growth of cells, silicon surface bio-functionalization was performed to study manipulation of mammalian cells such as fibroblasts as well as cervical and breast cancer cells. The manipulative property is attributed to a mixture of phases of silicon and silicon oxides as well as varied crystal orientations of silicon. It is hypothesized that the mixtures of phases on the substrate alter its surface morphology and consequently induce cell manipulation. Therefore, laser irradiated bio functionalized silicon and its nanostructures are a versatile material for biomedical applications. Based on the process of bio functionalization, both proliferation and cell control and manipulation was achieved in this thesis.


2021 ◽  
Author(s):  
Priyatha Premnath

Currently fabricated bio-matrices lack important characteristics such as nanometer scale, ‘bumpy’ morphology and an interlinked structure. Therefore, cells cultured on such matrices may not truly represent phenotypes of cells grown in the natural environment. This thesis deals with the synthesis of a three dimensional nanofibrous silicon matrix that is interlinked and possesses a ‘bumpy’ structure that mimics the natural extra cellular matrix. This silicon matrix can be tailored to suit applications of cell proliferation and manipulation. Cell-biomaterial studies show that osteoblasts and fibroblasts proliferated by 300% on three dimensional nanofibrous matrix compared to virgin silicon. To induce controlled cell proliferation, the addition of gold to the silicon matrix was perceived. The phase of gold was altered and combined with silicon forming a unique hybrid structure that prevented the growth of cells in areas of increased gold concentration. Increased gold concentration indicated lower adhesion forces and reduced zeta potentials which consequently lead to decreased cell growth. In addition, the interaction of cancer cells with the three dimensional silicon and gold-silicon hybrid nanofibrous network was studied. Results indicate a 96% reduction in cancer cells compared to virgin silicon. The reduction in cells is attributed to- different phases of silicon and silicon oxides in nanoparticle form, the encapsulation of cells by the nanofibers and apoptosis of cells owing to nanoparticles entering cells passively. To control the growth of cells, silicon surface bio-functionalization was performed to study manipulation of mammalian cells such as fibroblasts as well as cervical and breast cancer cells. The manipulative property is attributed to a mixture of phases of silicon and silicon oxides as well as varied crystal orientations of silicon. It is hypothesized that the mixtures of phases on the substrate alter its surface morphology and consequently induce cell manipulation. Therefore, laser irradiated bio functionalized silicon and its nanostructures are a versatile material for biomedical applications. Based on the process of bio functionalization, both proliferation and cell control and manipulation was achieved in this thesis.


2021 ◽  
Author(s):  
Veniamin Koshevoi ◽  
Anton Belorus ◽  
Ilya Pleshanov ◽  
Anton Timchenko ◽  
Roman Denisenko ◽  
...  

In this work composite structures based on a porous silicon were obtained and studied. Porous matrices were formed by electrochemical etching in aqueous solutions of hydrofluoric acid. Based on the obtained substrates, por-silicon (Si)/silver (Ag) and por-Si/zinc oxide (ZnO) composite structures were formed. These composites were functionalized by various methods (electro (E)-, thermo (T)-, electrothermal exposure) as a result of which the structures were modified. When studying the samples by scanning electron microscopy (SEM), it was concluded that silver nanoparticles actively diffused into the pores under these technological modes of functionalization. The por-Si/Ag and por-Si/ZnO composite structures were also studied using the following methods: infrared (IR) spectroscopy and Raman ultrasoft X-ray emission spectroscopy. Also, the photoluminescent characteristics of the samples were studied. Based on the obtained results, it was concluded that functionalization methods actively change the phase composition of structures and the optical properties of composites.


Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 275
Author(s):  
Sergey I. Pokutnyi ◽  
Lucjan Jacak

It is shown that in a germanium/silicon nanosystem with germanium quantum dots, the hole leaving the germanium quantum dot causes the appearance of the hole energy level in the bandgap energy in a silicon matrix. The dependences of the energies of the ground state of a hole and an electron are obtained as well as spatially indirect excitons on the radius of the germanium quantum dot and on the depth of the potential well for holes in the germanium quantum dot. It is found that as a result of a direct electron transition in real space between the electron level that is located in the conduction band of the silicon matrix and the hole level located in the bandgap of the silicon matrix, the radiative recombination intensity in the germanium/silicon nanosystem with germanium quantum dots increases significantly.


2021 ◽  
Author(s):  
Mansi Sharma ◽  
Jagannath Panigrahi ◽  
Vamsi K. Komarala

Doped nanocrystalline silicon thin films, in which silicon nanocrystallites are embedded in an amorphous silicon matrix, are emerging as carrier-selective contacts for next-generation silicon heterojunction solar cells.


2020 ◽  
Vol 846 ◽  
pp. 156433
Author(s):  
I.N. Demchenko ◽  
Y. Melikhov ◽  
M.S. Walczak ◽  
R. Ratajczak ◽  
K. Sobczak ◽  
...  

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