Registration Number
0212U006374,
0110U006288
, R & D reports
Title
Researrch and development of regular arrays of silicon nanowiresin dielectric matrix and resonant-tunneling structures.
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Head
Evtukh Anatoli Antonovych,
Registration Date
23-03-2012
Organization
Institute of Semiconductor Physics of National Academy of Sciences of Ukrain
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The report submitted in one volume has 44 pages, including figures 9, Table 1, the sources of literature 48. Keywords: electronic field emission, silicon nanowires, technology, gas-transport reactions, the work function, the enhancement of the electric field, the effective area of emission. The purpose of Phase: A Study of physical processes in the formation of silicon nanowires and the modeling of electron field emission from Si nanowires. The technology for production of silicon nanowires (NW Si) by gas-transport reactions has been developed. The technological regimes of the silicon nanostructures growth on semiconductor substrates have been determined. It was established that on the silicon substrate with a gold film of thickness d = 4-5 nm, a value of the growth time t = 5 min. precipitated crystals with an average diameter of ~ 50 - 60 nm and a height of about 100 - 200 nm. Increasing the growth time of nano-objects in 2 times led to the emergence of large-diameter crystals of ~ 70 - 110 nm. The simulation of the silicon whiskers growth kinetics by gas phase epitaxy by taking into account the growth mechanism of vapor-liquid-crystal. Taking into account that oversaturation was 0.33, the value of the kinetic coefficient of crystallization 3x10E6 cm / c has been estimated. The obtained values, namely: oversaturation, the radial growth rate, the kinetic coefficients are in good agreement with literature data. On the basis of fulfilled experiments it is possible to point on such regularities of the silicon nanowires growth: 1) at the first stage of growth the polycrystalline layer with a thickness of approximately 100 nm is formed on the substrate, 2) at the second stage, the growth of nanowires is realized. It is assumed that a polycrystalline layer is a tool for creating high local oversaturation in the regions of of the nanowires creations and thus is a necessary condition of the growth of nanowires. The simulation of physical processes at electron field emission (EFE) from Si nanowires (NW) has been performed and the main methods for the determination of emission parameters have been proposed. The method for calculating the parameters of the emission current-voltage characteristics includes: 1) finding the average value of the effective area of emission in narrow intervals of the work function, 2) replacement of the complex exponential function, which is a component of the Fowler-Nordheim (FN) equation by a polynomial of degree 2 in the equation FN. This method allows to significantly simplify the method for determination of the EFE parameters. The calculations of electron field emission parameters in the case of silicon tips, coated with ZnO film by using two methods, namely by comparing the slopes of the curves before and after coating with a thin film and with the help of theoretical calculations in accordance with the proposed method gave results which show that the deviations between the results is no more than 10%. This indicates of relatively high accuracy of determining the parameters of EFE when applying the proposed methodology for calculating of the parameters of the emission current-voltage characteristics. An original non-destructive technique for determining the stability of EFE from the I-V characteristics, based on the definition of short-term instability of the emission current at EFE, analyzing the decline in the average values of the current time has been proposed. It is obvious that emission cathodes that exhibit a low stability of EFE with long-time dependence of the current (I = f (t)), also have a greater spread of values for the emission current-voltage characteristics. Therefore, the proposed method reduces the requirements for work equipment and does not destroy the samples.
Product Description
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Євтух Анатолій Антонович
Лісовський Ігор Петрович
Литовченко Володимир Григорович
Романюк Борис Миколайович
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2020-04-02
