SYNTHESIS OF NANOWIRE NETWORKS FOR CHEMICAL GAS

SENSOR APPLICATIONS

 

A.Jishiashvili

Institute of Cybernetics.

Georgian Technical University.

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nm

nmmicrometer

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The purpose of this work:

• to synthesize the NW network using the new pyrolytic growth technology;

• to study the performance of fabricated gas sensor.

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InP core

Ga2O3 shell

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350

Applied Power (W)

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400

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750

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Sou

rce

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pera

ture

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C)

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Schematic of the experimental arrangement for the growth of In2O3 nanowires

Dependence of source temperature on the applied power

Dependence of source temperature on time

In2O(g) + 2H2O(g) = In2O3 + 2H2(g) ΔG= - 200kJ

In2O(g) + H2(g) = 2In + H2O(g) ΔG= - 126 kJ

XRD pattern of In2O3 nanowires(a); SEM images of tapered nanowires grown at 420°C (b-d).

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SEM images of nanowires (a-c); Energy Dispersive X-Ray pseudo-color images of nanowires grown at 420°C (e-d).

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a b

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SEM image of nanowires grown at 470ºC (a); High Resolution TEM image of VLS grown In2O3 nanowires (b) and corresponding SAE pattern.

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O2+e- O–2(ads)

O–2(ads)+e– 2O–

(ads)

2NH3+3O-(ads) N2+3H2O+3e-

Fabricated In2O3 nanowire network based gas sensor

Ti/Au contact layers

Oxygen mediated mechanism of NH3 sensing

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Variation of sensitivity with concentration of ammonia for In2O3 nanowire-based sensor at 300°C

Gas sensing characteristics of In2O3 nanowires for 800 ppm

of ammonia at different temperatures

Permissible exposure limit for ammonia is 35 ppm (Occupational Safety and Health Administration)

The results of this study demonstrate that :

• developed new pyrolytic technology may be successfully used for producing In2O3 nanowires;

• gas sensor fabricated on the base of In2O3 nanowire network can be used for detecting 10 ppm level of ammonia.

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Thank you