Electrochemically nanostructured Electrochemically nanostructured materials and its applications in materials and its applications in electronicselectronicsS. LazaroukS. Lazarouk

Belarusian State University Belarusian State University of Informatics and of Informatics and RadioelectronicsRadioelectronicsMinsk, BelarusMinsk, Belarus

Electrochemically nanostructured materials are formed by electrochemical anodization processes

Porous silicon and porous oxides of valve metals (Al, Ti, W, Nb) can be fabricated by this approach

Laboratory equipment

Equipment for electrochemical anodization on semiconductor wafers in industry production

Photoluminescent properties of porous silicon films

Porous silicon samples with photoluminescent peaks in different parts of the visible range

Typical photoluminescent spectrum of porous silicon film

Electroluminescent spectrum of porous silicon film

Porous silicon

Light emitting diodes (LEDs) based on porous silicon

Photo of fragment of optical interconnects based on porous silicon LED

Structures Applications

Schematical view of optical interconnects based on porous silicon LEDs

Pore diameters can be varied in the range from subnanometers up to few microns

Photo of porous silicon

Fast oxidation processes in porous silicon films

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Explosion

CombustionFragments of combustion processes

Fragments of explosion processes

Light emission kinetics at fast porous silicon oxidation processes

Applications:ecologically clean pyrotechnics.self-destructed chips,ignition system for airbag in automobiles,alternative fuel in respect with carbon and hydrocarbon fuels.

MEMS based on energy of porous silicon combustion

Schematical view of MEMS based on porous silicon

Cross-sectional photo of silicon chip with porous silicon for MEMS

Porous silicon impregnated by solid state oxidant

Porous silicon combustion

Direction of silicon chip movement

Schematical view of MEMS operation

The estimated impulse ranges from 1 to 10 mN·s, which is very promising for a use of porous silicon as an energetic material in MEMS.

Porous alumina

Porous alumina with the tradition cell structure (honey comb cell

structure)

Applications

Planar aluminium VLSI interconnects built in porous alumina: a) surface view; b) cross-sectional view.

Porous alumina with the tubular cell structure

Porous alumina with the tubular structure can be used for vertical alignment of liquid crystal materials in display devices

Schematical view of vertical alignment of liquid crystal

molecules in porous alumina

Structures

Porous oxides of refractory metals (Ti, W)

Photographs of porous titanium and tungsten oxides with different structures : а – tubular structure (cross-sectional view ), b – doublewall tubular structure (surface view), c – sponge like structure (cross-sectional view), d – pillar structure (cross-sectional view).

Applications:Porous oxides of refractory metals can be used: - for photocatalitic water purification from organic pollutions;- for anodes in electrochromic displays;- for anodes in pfotoelectrolis cells for water splitting to hydrogen and oxygen

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Conclusion

Nanostructured oxides of valve metals are promissing materials indeed for photocatalysis, sensor and electrooptical applications

Nanostructured porous silicon LEDs open new possibilities for developing silicon based optoelectronics

Nanostructured silicon can be considered as an alternative energetic material in respect of carbon based fuels