A micro optofluidic system for toluene detection application

Ramezannezhad, Mohammad; Nikfarjam, Alireza; Hajghassem, Hassan; Akram, Mohammad Makhdoumi; Gazmeh, Meisam

doi:10.1016/j.mee.2019.111204

Cited by 4 publications

(4 citation statements)

References 32 publications

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“…Electrical and optical methods are two common ways for gas sensing purpose [7]. Electrical methods are approximately inexpensive for gas detection, however, most of them suffer from lack of suitable selectivity [7].On the other hand, in spite of significant selectivity of the optical based methods, they are relatively costly [7,8].…”

Section: Introductionmentioning

confidence: 99%

Planar microplasma optical emission gas spectroscopy based on selective growth of ZnO nanowires

Ramezannezhad

Nikfarjam

Sichani

et al. 2022

Micro & Nano Letters

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The present study demonstrates a novel miniature planar device by the selective growth of ZnO nanowires for microplasma optical emission gas spectroscopy. Gold electrodes are fabricated on the silicon substrate by thermal evaporation and photolithography process with a 15 μm gap size. Zinc oxide (ZnO) nanowires, are selectively grown on the electrodes without using a seeding layer by a hydrothermal method which is a cost‐effective approach. Growth of vertically aligned ZnO nanowires on electrodes with sharp tips reinforce the field emission enhancement factor which results in lower microplasma generation voltage. The SEM characterizations reveals that ZnO nanowires are grown on electrodes, selectively. The diameter range and length of nanowires vary between 50 and 250 nm and 3 and 5 μm, respectively. Also, the gap distance between electrodes decreases from 15 μm to about 4–10 μm due to the growth of vertically aligned nanowires. The experimental tests are implemented for helium, nitrogen, and carbon dioxide gases at room temperature and atmospheric pressure. The results successfully exhibit the characteristic peaks and repeatable responses for all the samples. In addition, the required working voltage for microplasma formation of He, N2, and CO2 reduce 32%, 22%, and 20%, respectively, after ZnO nanowires growth. Besides, the electrodes sputtering rate significantly decreases during the tests due to the thermal stability of ZnO nanowires. According to the device performance, the proposed structure could be a promising candidate for relative low voltage, highly selective and stable optical emission spectroscopy for gas detection applications.

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Section: Introductionmentioning

confidence: 99%

Planar microplasma optical emission gas spectroscopy based on selective growth of ZnO nanowires

Ramezannezhad

Nikfarjam

Sichani

et al. 2022

Micro & Nano Letters

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“…Being costly, inability to form a miniaturized size channel which leads to complex and large structure and chamber assembly problems are notable materials difficulties (de Hoyos-Vazquez et al, 2019;Shen and Yeah, 2019). On the other hand, poly(methyl methacrylate) (PMMA), as one of the well-known polymers, has been used in some optical detection systems as for channel fabrication (Pujol-Vila et al, 2016;Ramezannezhad et al, 2020). However, PMMA may not have such strength like metals, it has several unique properties such as low cost, existence of different simple methods for its assembly, capability for miniaturized channel fabrication and low weight, which can make it a suitable candidate to use for chamber fabrication (Ramezannezhad et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, poly(methyl methacrylate) (PMMA), as one of the well-known polymers, has been used in some optical detection systems as for channel fabrication (Pujol-Vila et al, 2016;Ramezannezhad et al, 2020). However, PMMA may not have such strength like metals, it has several unique properties such as low cost, existence of different simple methods for its assembly, capability for miniaturized channel fabrication and low weight, which can make it a suitable candidate to use for chamber fabrication (Ramezannezhad et al, 2020). Moreover, it has a smooth surface which is appropriate for different material deposition.…”

Section: Introductionmentioning

confidence: 99%

Low cost and miniaturized NDIR system for CO₂ detection applications

Akram

Nikfarjam

Hajghassem

et al. 2020

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Purpose The importance of Carbon dioxide (CO2) gas detection as a greenhouse and exhale breathe gas is an undeniable issue. This study aims to propose a new miniaturized, low cost and portable no dispersive infrared (NDIR) system for detecting CO2 gas. Design/methodology/approach Poly(methyl methacrylate) (PMMA)-based channels with Au coating because of its high reflection properties in IR region were used in this work. The optical windows were fabricated using PDMS polymer which is cost effective and novel in comparison to other conventional methods. The effects of channel dimensions, lengths and entrance angle of light on optical path length and losses were analyzed with four types of channel using both simulation and experimental tests. Findings The simulation results indicate that the 0 degree light entrance angle is the most efficient angle among different investigated conditions. The experimental data are in agreement with the simulation results regarding the loss and optical path length in different types of channel. The experimental tests were performed for the 0.5% up to 20% of CO2 concentration under constant temperature and humidity condition. The results show that the device with 5 and 2 cm channels length were saturated in 4% and 8% concentration of CO2 gas, respectively. Response and recovery times were depending on gas concentration and channels specifications that in average found to be 10 S and 14 S, respectively, for the largest size channel. Moreover, the environment humidity effect on detection system performance was investigated which had no considerable influence. Also, the saturation fraction absorbance value for devices with various dimensions were 0.62 and 0.8, respectively. Practical implications According to the performed curve fitting for practical situation and selected CO2 concentration range for experimental tests, the device is useful for medical and environmental applications. Originality/value PMMA with Au deposition layer was used as a basic material for this NDIR system. Besides, a novel PDMS optical window helps to have a low cost device. The effects of channel dimensions, lengths and entrance angle of light on optical path length and losses were analyzed using both simulation and experimental tests. Using narrowband optical filter (100 nm bandwidth) helps to have a system with good CO2 selectivity. In addition, experimental tests with different channel dimensions and lengths covered a considerable range of CO2 concentration useful for medical and environmental applications. Finally, curve fitting was adopted for a modified Beer–Lambert law as a practical situation.

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“…Hence, it can be said that the research and application of PVD techniques are living a scientific golden age due to the large amount of exciting new possibilities, fundamental discoveries, and the numerous potential applications based on their wide range of morphological characteristics and properties, e.g. in photovoltaic cells [ 8 ], tribological coatings [ 9 , 10 ], optofluidic sensors [ 11 ], energy storage [ 12 ], etc.…”

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confidence: 99%

Editorial for Special Issue: Nanostructured Surfaces and Thin Films Synthesis by Physical Vapor Deposition

2021

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A micro optofluidic system for toluene detection application

Cited by 4 publications

References 32 publications

Planar microplasma optical emission gas spectroscopy based on selective growth of ZnO nanowires

Planar microplasma optical emission gas spectroscopy based on selective growth of ZnO nanowires

Low cost and miniaturized NDIR system for CO₂ detection applications

Editorial for Special Issue: Nanostructured Surfaces and Thin Films Synthesis by Physical Vapor Deposition

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A micro optofluidic system for toluene detection application

Cited by 4 publications

References 32 publications

Planar microplasma optical emission gas spectroscopy based on selective growth of ZnO nanowires

Planar microplasma optical emission gas spectroscopy based on selective growth of ZnO nanowires

Low cost and miniaturized NDIR system for CO2 detection applications

Editorial for Special Issue: Nanostructured Surfaces and Thin Films Synthesis by Physical Vapor Deposition

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Low cost and miniaturized NDIR system for CO₂ detection applications