intense and energetic atmospheric pressure plasma jet arrays

Full Paper

Intense and Energetic Atmospheric PressurePlasma Jet Arraysa

Jae Young Kim, John Ballato, Sung-O Kim*

Intense and energetic atmospheric plasma emissions were achieved by direct jet-to-jetcoupling using honeycomb-structured quartz tube arrays. Two plasma modes were foundto exist in the same plasma array structure under a change of gas flow conditions: an intenseplasma mode and the well-collimated plasma mode. In order to describe the direct jet-to-jetcoupling by electrical coupling of charged particles in the plasma, the optical emission of theplasma array was compared with that of a singletube plasma jet. Under identical electrical drivingand gas conditions, the optical intensity from theintense plasma jet was approximately four timeslarger in the coupled array than in the singleplasma jet structure. Additionally, the electronenergy in the intense plasma was larger thanthat of the well-collimated plasma jets in thesame device. This intense and energetic plasmajet, arising through direct jet-to-jet coupling, mayprovide novel applications requiring strong dis-charge processes using simplified structures andaccompanying instrumentation when comparedwith the present vacuum plasma systems.

1. Introduction

The use of an atmospheric pressure plasma jet (APPJ) device,

consisting of a tube with carrier gases and electrodes, is

Dr. J. Y. Kim, Prof. S.-O KimHolcombe Department of Electrical and Computer Engineering,Center for Optical Materials Science and EngineeringTechnologies (COMSET), Clemson University, Clemson,South Carolina 29634, USAE-mail: [email protected]. J. BallatoSchool of Material Science and Engineering, Center for OpticalMaterials Science and Engineering Technologies (COMSET),Clemson University, Clemson, South Carolina 29634, USA

a Supporting Information for this article is available from the WileyOnline Library or from the author.

Plasma Process. Polym. 2012, 9, 253–260

� 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim wileyonlin

perhaps one of the most useful devices for creating non-

thermal atmospheric pressure plasmas.[1–10] These APPJs,

however, are based upon weakly ionized discharge and

their emitting intensities are relatively low in comparison

to low pressure plasmas created using vacuum chambers.

Because such deficiencies can limit the diversity of

applications of these plasma jets, plasma jet focusing has

been undertaken to increase the discharge rate of plasmas

at one atmosphere pressure.[11] Plasmas are gaseous

collections of ionized charged particles that include

electrons, ions, and short-lived free radicals.[12–17] If the

plasma jet from each single plasma jet device is proximate

to each other through an arrayed structure, the collections

of charged particles interact with each other at certain

discharge conditions, thus affecting the discharge beha-

viors in a collective manner. As such, these plasma jets

discharging adjacent to each other ultimately bundle

elibrary.com DOI: 10.1002/ppap.201100190 253

Figure 1. Two different plasma plumes from the plasma array device. (A) The concen-trated plasma plume and (B) seven well-collimated plasma plumes between the plasmaarray device and the glass side of the ITO electrode with change in gas velocity.

254

J. Y. Kim, J. Ballato, S.-O Kim

together to form a strongly coupled

Coulomb system. Attempts have been

undertaken to develop one- or two-

dimensional array structures to generate

atmospheric plasmas via the extension of

the plasma size for the uniform treat-

ment of a large area.[18–23] There is as yet,

however, little research on the plasma

jet-to-jet coupling to improve plasma

emitting intensity in the plasma jet

arrays at atmospheric pressure.

The emphasis of the effort described

herein was the development of the

intense plasma emission induced by

jet-to-jet coupling in the plasma jet array

device at atmospheric pressure. In order

to investigate the concentration phe-

nomena of the plasma plumes by jet-

to-jet coupled behavior, the optical emis-

sions of the plasma jet array were

observed using the photo sensor amplifier and the fiber

optic spectrometer. The electron energies in the intense and

normal plasma jets were characterized and discussed using

optical emission spectroscopy (OES). Utilizing an intense

plasma jet based on helium gas, plasma etching of glass was

successfully achieved indicating the energetic nature of

these coupled plasma arrays. Lastly, the plasma array with a

large-sized honeycomb structure was investigated to

extend further the conceptual idea of the coupled jet

intense plasma arrays.

2. Experimental Section

Figure 1 shows the plasma jet array device comprising seven quartz

glass (silica) tubes. The shape of the plasma jet array device is a

honeycomb structure with a single tube in the center of the array

with the remaining six tubes surrounding the centered tube. Each

quartz tube, within this array, has an inner diameter length of

1 mm and an outer diameter length of 2 mm, with the center-to-

center distance between the two adjacent quartz tubes at 2.4 mm.

For the powered electrode within each quartz tube copper tape

6 mm in width was used and placed 10 mm apart from the end of

the tube. The seven tubes were combined through the powered

electrode with the copper tape. An indium tin oxide (ITO)-coated

glass plate of 0.8 mm thickness was placed 10 mm from the ends of

the quartz glass tube array and served as the ground electrode. The

glass side faced the plasma jets. During the discharge process, a

plasma plume was observed between the powered and ground

electrodes, and a high purity helium gas (99.999%) was used as the

discharge gas. In order to observe the input electric energy, the

voltage and current waveforms emanating from the powered

electrode were measured using a high voltage probe (Tektronix

P6015A) and a current monitor (Pearson 4100). An inverter circuit

was used to amplify a low primary voltage to a high secondary

voltage. The driving circuit generated a sinusoidal voltage of


� 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

several tens kilovolts with a frequency of several tens of kilohertz,

and the photo sensor amplifier (Hamamatsu C6386-01) was used to

observe plasma emissions. The wavelength-unresolved optical

emission waveform from the photo sensor amplifier encompassing

the wavelength ranges of 400–1 100 nm was then plotted on the

oscilloscope (Tektronix TDS3014C). In the front of the photo sensor

amplifier, an optical slit of 1 mm in width was used to obviate

external environmental light. A fiber optic spectrometer (Ocean

Optics, USB-4000UV–VIS) was employed to identify the miscellany

of reactive species and to estimate the electron energy in the

plasma plume.

3. Results and Discussion

3.1. Plasma Emission Modes From Honeycomb

Structured Glass Tubes

When the sinusoidal voltage waveform with the peak

voltage of 10 kV and the frequency of 32 kHz (the

corresponding input power of 28 W) was applied to the

powered electrode, the plasma plume between the plasma

jet array device and the glass side of the ITO glass exhibited a

different appearance, due to the change in linear gas

velocity. First, at the linear velocity of He gas of up to

4.6 m � s�1, the corresponding gas flow rate of 1.5 slm

(standard liter per minute), the plasma plume from the

plasma jet array did not reach the ITO glass. At the range of

the He gas velocity from 4.6 to 10.6 m � s�1, and a

corresponding gas flow rate of 1.5–3.5 slm, the plasma

plume was highly concentrated at the center quartz glass

tube. A concentrated plasma plume with a stronger plasma

emission was observed under these conditions. An increase

in the linear velocity of He gas to 10.6 m � s�1 or over, and

an increase in the corresponding gas flow rate above

DOI: 10.1002/ppap.201100190

Intense and Energetic Atmospheric Pressure Plasma Jet Arrays

3.5 slm transformed the plasma into seven well-collimated

plumes (see Supporting Videos 1 and 2). Though the gas

flow became turbulent at extremely large flow rates of He

gas, 15 slm and over, thusly causing unstable discharges,

the plasma plumes are still well aligned and parallel to each

other. Figure 1A and B also show the photographs of two

different plasma jet modes as a change in gas velocities.

Figure 1A shows the intense plasma jet at the gas velocity of

9.1 m � s�1 (the corresponding gas flow rate of 3.0 slm). The

outer quartz glass tubes surrounding the centered quartz

tube, however, did not produce strong individual plumes

but instead reinforced the centered plasma plume, despite

the presence of an equally distributed gas flow. These

results were confirmed through direct observation of a

much more incandescent plasma jet at the center tube of

the array than a well-collimated atmospheric plasma jets.

The six outer plasma plumes were weakened in this

arrangement, however, indicating that an intense plasma

jet is driven by direct jet-to-jet coupling in the air.

Conversely, Figure 1B shows the well-collimated seven

plasma jets at a gas velocity of 15.2 m � s�1 (the gas flow rate

of 5.0 slm). The plasma plumes from seven tubes were well

aligned and parallel to each other under this condition.

The experimental conditions necessary for a successful

plasma jet-to-jet coupling for an intense plasma were

empirically determined; each single plasma jet from the

plasma array must be close enough to each other for easy

interaction; the plasma device must have a single electrode

configuration and a ground electrode several centimeters

apart from the array is needed; and the plasma array must

have an appropriate gas flow rate of around 1–3.5 slm.

When the gas flow rate was higher than 3.5 slm in this

experimental set-up, the plasma jets no longer interacted

with each other, but rather transformed into well-

collimated plasma plumes regardless of operating voltage.

The plasma jet-to-jet coupling behavior is caused by not

optical coupling nor chemical coupling, but electrical

coupling of charged particles. The plasma jet-to-jet coupling

behavior is certainly caused by a use of common ground

electrode. When the seven individual plasma jets propel

toward one common ground electrode, the produced

charged particles from the individual plasma jets would

be merged to each other and concentrated along a certain

discharge path between the powered and ground electrodes

where the discharge can be produced easily at certain

experimental condition. In order to investigate the

concentration phenomena of the plasma plumes by the

direct jet-to-jet coupling among the adjacent plasma

plumes, the plasma emission properties of the plasma jet

array device and the single tubing plasma jet device were

examined and compared as a function of linear gas velocity.

When comparing the characteristics of the plasma plume,

the single quartz glass tube plasma jet device was identical

to one element of the plasma jet array. When the applied



input power was fixed to 28 W, the plasma emissions from

both plasma devices were monitored as an increase of the

linear gas velocity. Under the same power conditions, the

applied sinusoidal voltage waveforms were the peak

value of 10 and 11 kV for the plasma jet array and the

single tubing plasma devices, due respectively to the

impedence difference of two plasma devices. The photo

sensor amplifier with 1 mm-wide optical slit was aligned

with the positions of the centered plasma plume from the

plasma array and the plasma plume of the single tubing

plasma device, respectively. As a result, the optical intensity

of the plasma emission in both plasma devices exhibited

different tendencies with an increase of gas velocity as

shown in Figure 2. Since no jet-to-jet coupling was observed

in the single tubing plasma jet, the optical intensity

increased with a corresponding increase in the linear gas

velocity. The optical intensity of the centered plasma plume

from the plasma jet array abruptly decreased between the

gas velocity of 9.1 and 12.1 m � s�1, however, with a change

of the plasma jet mode in the plasma jet array.

Figure 2 shows the optical intensity of a plasma emission

of a single plasma jet and the array device at linear gas

velocities between 6.1 and 15.2 m � s�1. Regarding the single

tubing plasma jet device, the corresponding gas flow rates

varied from 285 to 715 sccm (standard cubic centimeters

per minute; 1 000 sccm¼ 1 slm), whereas the gas flow rates

of 2.0 to 5.0 slm corresponded with the gas velocities of the

plasma jet array device. The optical intensity of plasma

emission in rising slope of the voltage waveform is shown

to be higher than that in the falling slope in both single

tubing plasma and plasma array in Figure 2. This difference

of the optical intensities is caused by the different shapes

between the powered and ground electrodes. Our proposed

plasma system which consists of the plasma array with a

single electrode configuration and an outside ground

electrode can be classified as a point-to-plane discharge

configuration. The difference of the optical intensities

between rising and falling slopes of the voltage waveform is

a stereotypical discharge property of point-to-plane barrier

discharges driven by ac voltages. The streamer-like

discharge mode in the positive half-period and the

diffuse-like discharge mode in the negative half-per-

iod.[24,25] Therefore, when the powered electrode plays a

role of an anode and the ITO ground electrode play a role of a

cathode, stronger plasmas are generated than vice-versa.

While the optical intensity increased by 85% with an

increase in the gas velocity from 6.1 to 15.2 m � s�1 for the

plasma plume discharged from a single tube, the optical

intensity of the centered plasma plume decreased by 40%

for the plasma plume discharged from the plasma jet array.

At a gas velocity of 9.1 m � s�1, the optical intensity of the

centered plasma plume from the plasma jet array was four

times larger than the plasma plume from the single tube,

despite identical power and gas conditions. Here, the seven

www.plasma-polymers.org 255

Figure 2. Optical intensity of plasma plumes from the single tube plasma jet and the intense plasma jet array devices at various gasvelocities from 6.1 to 15.2m/s.

256


plasma jets from the plasma jet array begin to interact with

each other under this precise condition to reinforce the

centered plasma plume by this coupling effect among the

seven plasma jets when the six outer plasma plumes were

weakened. The three pairs of outer quartz glass tubes facing

each other that surround the centered quartz tube plus the

center tube comprising the four jet-to-jet couplings yield an

optical intensity four times greater than in previous

experimentation. Interestingly, at the gas velocity of

15.2 m � s�1 in the well-collimated plasma mode, the optical

intensity of the centered plasma plume from the plasma

array is also 1.4 times greater than the plasma plume from

the single tube, despite identical power and gas conditions.

Though this increase does not occur in the jet-to-jet

coupling phenomenon in the well-collimated mode within

the seven plasma plumes, there is electrical coulping of

charged particles between closed adjacent plasma plumes,

thusly enhancing slightly the plasma emission. There are

increases in the amplitudes of the produced plasma

emission at not only the rising slope but also the falling

slope of the input voltage in the intense plasma mode as

shown in Figure 2. Since the operating voltage condition

(Vp ¼ 10 kV and Freq.¼ 32 kHz) is not changed with the



plasma mode transition, this higher emission in the intense

plasma mode is indicative of both a greater maximum

intensity, and an improved average discharge rate than the

well-collimated plasma mode.

3.2. Optical and Plasma Emitting Behaviors of Intense

Plasma Jet at Atmospheric Pressure

OES is a non-invasive method for investigating atoms, ions,

and molecules in a plasma media.[26–28] Its diagnostic use

for emitting media has yielded a greater understanding of

very complex phenomena such as high gas pressure

plasmas.[29] In order to verify the reactive species generated

by the intense helium APPJ in the ambient air, the emission

spectra of two different plasma jet modes were monitored

and compared using the fiber optic spectrometer in which

the distance between the end of the device and the

spectrometer was fixed at 10 mm. Figure 3A and B show the

emission spectra from 300 to 800 nm of two different

plasma modes, further indicating that the excited N2, Nþ2 ,

He, H, and O exist in the plasma plumes. As is observed in

these figures, the optical emission spectra of the intense

plasma jet mode exhibited strong intensity levels of

DOI: 10.1002/ppap.201100190

Figure 3. Comparison of optical emission spectra of two different plasma plumes: The optical emission spectra of plasma plumes between(A) the intense plasma mode and (B) the well-collimated plasma mode under identical input driving conditions; (C) and (D) Magnifiedemission spectra of second positive systems of nitrogen.


nitrogen and oxygen species that are highly reactive

radicals compared to the spectra of the well-collimated

plasma jet. Note also that the emission spectra of the

intense plasma jet only exhibits the oxygen atomic lines at

533 nm and 615 nm, and the hydrogen atomic line at

656 nm, which is likely due to humidity from the air. These

results imply that the higher emission of the intense

plasma jet is indicative of not only stronger atomic

intensity levels, but also an improved discharge rate. The

emission spectra observations are well matched with the

results of the optical emission intensity.

In order to determine if the proposed intense plasma

exhibited higher electron energy than the well-collimated

plasma, the properties of electron energy of two different

plasma modes were characterized and compared by peaks

of both first negative and second positive systems of

nitrogen using OES. Figure 3C and D show the magnified

emission spectra of the second positive systems and the

first negative system of nitrogen. Note that the nitrogen

molecule is transferrable from the ground state N2(X1Pþg )

into an excited state N2(C3Pu) by the impact of electrons

with an energy >11.0 eV. Subsequently, the excited

N2(C3Pu) molecules transferred into the N2(B3Pg) state



by emitting a proton of 337.1 nm in wavelength. If electrons

exhibit energy >18.7 eV, nitrogen ions Nþ2 (B2Pþ

u ) will be

produced that release photons of 391.4 nm in wavelength

via transfer into the Nþ2 (X2Pþ

g ) state. Based on these

different emitting procedures of nitrogen, the relative

changes in the concentration of active species N2(C3Pu) and

Nþ2 (B2Pþ

u ) in two different plasma modes can be monitored

by measuring the emission intensities at 391.4 nm and

337.1 nm.[30–32] The normalized emission intensity at

391.1 nm (an emission intensity at 391.4 nm divided by

an emission intensity at 337.1 nm) of the intense plasma

mode is revealed to be 1.5 times greater than that of the

well-collimated plasma mode (i.e., the normalized emission

intensities at 391.1 nm indicate that the electron energy of

the intense plasma mode is relatively greater than that of

the well-collimated plasma mode).

3.3. Temperature Variation on the Surface of ITO

Glass by Plasma Jet Emissions From a Seven Tube

Honeycomb Array and a Single Tube

Figure 4 shows the temperature variation of the surface of

ITO glass as a function of time when the plasma plume


Figure 4. Temperature variation of the ITO glass as a function oftime when the plume from single tube plasma jet and plasma jetarray devices reaches the glass side of the ITO glass.

258


makes contact with the glass side of the ITO glass electrode.

The applied input power was also fixed to 28 W with

frequency of 32 kHz.

The ITO glass temperatures were measured using the

infrared thermometer (Extech IR Thermometer 42545) with

the measuring point being the center of the plasma plume

on the glass surface of the ITO glass. The initial ITO glass

temperature is 25 8C. Regarding the plasma jet emissions

from the single tube, the ITO glass temperatures became

saturated at 150 s. When the gas velocities through the

single tube were 9.1 and 15.2 m � s�1, the saturated

temperatures of the ITO glass via plasma jet from the

single tube were 37 and 32 8C, respectively. This tempera-

ture difference likely is due to neutral He gas flows. An

acceleration of the gas velocity also resulted in a rapid

increase of neutral He gas flow that quickly cooled the

surface of the ITO glass. Regarding the plasma jet array

device, the ITO glass temperature becomes saturated at

approximately 150 s at a gas velocity of 15.2 m � s�1, and at

240 s at a gas velocity of 9.1 m � s�1, respectively. Gas

velocities through the plasma jet array device at 9.1 m � s�1

and 15.2 m � s�1 yield saturated temperatures of 81 and

67 8C, respectively. Though the input power and the

distance between the powered and ground electrodes are

identical, the saturated temperature on the ITO glass caused

by plasma jet arrays is more two times greater than that

with a single plasma jet, regardless of the plasma jet modes.

3.4. Glass Etching by Intense Helium Atmospheric

Pressure Plasma

It can be concluded from these experimental results that an

intense and energetic plasma process occurs in the



concentrated plasma jet; i.e., this jet-to-jet coupling

behavior exhibits greater electron energy than either the

single plasma jet or the seven well-collimated plasma jets.

The observation of plasma etching on the glass confirms

that the proposed plasma jet is an energetic plasma. Despite

the use of the helium gas at atmospheric pressure, the

etching by the concentrated plasma jet strongly and quickly

occurs on the glass as shown in Figure 5. When the

concentrated plasma plume begins to etch a glass, the

plasma plume is no longer reflected upon the glass surface,

but instead penetrates the spot as shown in Figure 5A. No

etching occurs, despite an increase in input powers and

treated times of the single plasma jet and the well-

collimated plasma mode. Figure 5B shows the resultant

etched spots on the glass surface of ITO-coated glass from

the concentrated plasma plume, in which a total of 30 (6 by

5) etched spots on the glass with an area of 10 cm� 10 cm

were created. Figure 5C and D show SEM images of one

etched spot from the intense and energetic plasma jet on

the glass. As shown in the SEM images, many-ion

bombardments on the glass are observed in a single etched

spot, which caused a physical etching of the glass during the

plasma processes. As shown in Figure 5C, the non-

uniformity of the etching process was observed inside

the spot. The intense plasma jet driven by sinusoidal

voltage with several kilohertz temporally consists of a large

number of micro-discharges with a short duration (in

microseconds), which are spatially randomly distributed

between powered and ground electrodes. The micro-

discharges are produced along a certain discharge path

where the discharge can be produced easily, resulting in

filamentary discharge, which is represented as ‘‘plasma

concentration’’. Since the filamentary discharge character-

istics show not only non-uniformity but also spatial

randomness, the non-uniformity of the etching process

can be observed inside the etched spot. This physical

etching in turn reveals substantial evidence of the energetic

plasma process involving the charged particle transport in

the concentrated plasma jet channel by direct jet-to-jet

coupling.

3.5. Plasma Jet Emissions From Honeycomb

Structured Nineteen Tube Arrays

In order to extend the conceptual idea of the intense plasma

jet with direct jet-to-jet coupling, the honeycomb struc-

tured and triplely-coupled nineteen tube array was

developed as is shown in Figure 6A. The 19-array is

constructed such that the central tube protrudes 1 mm from

other tubes for an easier ignition of the plasma. The

discharge gas was high purity helium, flowing at a rate of

4.0 slm. The intense plasma plume generated from this

configuration is illustrated in Figure 6B. Note the direct jet-

to-jet coupling behavior. Despite an equally distributed gas

DOI: 10.1002/ppap.201100190

Figure 5. Plasma etching from the intense plasma jet generated from the plasma array device: (A) A photograph of concentrated plasmaplume focused on the etched spot; the plasma starts to etch the glass within 10 s, (B) etched spots from a concentrated plasma jet on theglass side: (C) and (D) SEM images of one etched spot by a concentrated He plasma jet on the glass.


flow, the outermost tubes do not produce strong individual

plumes. Rather, the plasma flow from these tubes is drawn

into the central plume, which is in turn amplified. Using a

photo sensor amplifier, the plasma emission properties

among 19- and 7-array plasma jet devices and the single

tubing plasma jet device were quantified and compared.

While the input power of the applied sinusoidal voltage

waveform was fixed to 28 W at 30 kHz, the gas flow rates of

19- and 7-arrays and a single jet were varied to 4.0, 2.5, and

1.0 slm, respectively, which are the experimentally opti-

mized flow conditions for the maximum optical intensity

of each plume under the same input power. As seen in

Figure 6C under these experimental conditions, the optical

intensity of plasma plumes created by jet arrays increases

with the number of tubes in the array. The 19-array yields a

much greater optical intensity compared to either the 7-

array or single tube. Compared to a solitary tube, a seven-jet

array possesses approximately triple the optical intensity,

while the 19-array possessed almost five times the optical

intensity. The discharge delays of coupling effect, observed

among the three devices, indicates that the coupling effect

requires time for mutual interaction as shown in Figure 6C.

That is to say the coupling effect can be controlled by

changing parameters and structural design according to

their purpose and applications.



4. Conclusion

Described in this work was the initial development of an

intense and energetic plasma jet mode from a honeycomb

structural APPJ array. The discharge modes between the

intense plasma and well-collimated plasma jets were

observed to transform to a linear gas velocity. At

identical conditions of input power and linear velocity

of the helium gas condition, the optical intensity from

the centered plasma jet of the plasma jet array with

seven tubes was four times greater than a single plasma

jet. Compared to the well-collimated jet spectra, the

emission spectra of the intense plasma jet also

exhibited both strong intensity levels of nitrogen and

oxygen species and more reactive oxygen and hydrogen

species. In addition, the normalized emission intensities at

391.1 nm indicate that the electron energy of the intense

plasma jet was greater than that of the well-collimated

plasma jet. The triple coupled 19-array exhibited a

fivefold greater optical intensity compared to the single

tube and double larger than the 7-array. The intense and

energetic plasma jet by the direct jet-to-jet coupling is

useful for determining the accuracy of applications

requiring the high energetic plasmas, using only a very

elemental apparatus.


Figure 6. 19-array APPJ array device: (A) 19-array APPJ array struc-ture and (B) intense plasma plume from this plasma jet arraydevice: (C) Comparison of optical intensity of plasma plumesamong 19- and 7-APPJ arrays and a single jet at maximum plasmaemission conditions.

260


Acknowledgements: The authors wish to acknowledge thefinancial assistance of the Center for Optical Materials Scienceand Engineering Technologies (COMSET) at Clemson Universityand the editorial assistance of Mr. Godfrey Kimball, also atClemson University.

Received: October 20, 2011; Revised: December 19, 2011;Accepted: January 6, 2012; DOI: 10.1002/ppap.201100190



Keywords: atmospheric pressure plasma jet; concentrated plasmaplume; jet-to-jet coupling; plasma array

[1] B. L. Sands, B. N. Ganguly, K. Tachibana, Appl. Phys. Lett. 2008,92, 151503.

[2] N. Jiang, J. Yang, F. He, Z. Cao, J. Appl. Phys. 2011, 109, 093305.[3] J. F. Kolb, A.-A. Mohamed, R. O. Price, R. J. Swanson,

A. Bowman, R. L. Chiavarini, M. Stacey, K. H. Schoenbach,Appl. Phys. Lett. 2008, 92, 241501.

[4] N. Jiang, A. Ji, Z. Cao, J. Appl. Phys. 2009, 106, 013308.[5] H. Kim, A. Brockhaus, J. Engemann, Appl. Phys. Lett. 2009, 95,

211501.[6] H. W. Lee, S. H. Nam, A.-A. H. Mohamed, G. C. Kim, J. K. Lee,

Plasma Process. Polym. 2010, 7, 274.[7] J. Y. Kim, S.-O. Kim, Y. Wei, J. Li, Appl. Phys. Lett. 2010, 96,

203701.[8] J. Y. Kim, Y. Wei, S.-O. Kim, Biosens. Bioelectron. 2010, 26, 555.[9] J. Y. Kim, Y. Wei, J. Li, P. Foy, T. Hawkins, J. Ballato, S.-O. Kim,

Small 2011, 7, 2291.[10] J. Y. Kim, J. Ballato, P. Foy, T. Hawkins, Y. Wei, J. Li, S.-O. Kim,

Biosens. Bioelectron. 2011, 28, 333.[11] K. Yambe, H. Sakakita, H. Koguchi, S. Kiyama, N. Ikeda,

Y. Hirano, J. Plasma Fus. Res. Ser. 2009, 8, 1322.[12] M. J. Kushner, J. Phys. D Appl. Phys. 2005, 38, 1633.[13] K. H. Becker, K. H. Schoenbach, J. G. Eden, J. Phys. D Appl. Phys.

2006, 39, R55.[14] T. Somekawa, T. Shirafuji, O. Sakai, K. Tachibana,

K. Matsunaga, J. Phys. D Appl. Phys. 2005, 38, 1910.[15] M. Cooper, G. Fridman, D. Staack, A. F. Gutsol, V. N. Vasilets,

S. Anandan, Y. I. Cho, A. Fridman, A. Tsapin, IEEE Trans.Plasma Sci. 2009, 37, 866.

[16] Q.-Y. Nie, C.-S. Ren, D.-Z. Wang, J.-L. Zhang, Appl. Phys. Lett.2008, 93, 011503.

[17] Y. C. Hong, H. S. Uhm, Phys. Plasmas 2007, 14, 053503.[18] E. E. Kunhardt, IEEE Trans. Plasma Sci. 2000, 28, 189.[19] Y.-B. Guo, F. C.-N. Hong, Appl. Phys. Lett. 2003, 82, 337.[20] X. Lu, Q. Xiong, Z. Tang, Z. Jiang, Y. Pan, IEEE Trans. Plasma Sci.

2008, 36, 990.[21] Z. Cao, J. L. Walsh, M. G. Kong, Appl. Phys. Lett. 2009, 94,

021501.[22] Q. Y. Nie, Z. Cao, C. S. Ren, D. Z. Wang, M. G. Kong, N. J. Phys.

2009, 11, 115015.[23] Z. Cao, Q. Nie, D. L. Bayliss, J. L. Walsh, C. S. Ren, D. Z. Wang,

M. G. Kong, Plasma Sources Sci. Technol. 2010, 19, 025003.[24] Y. S. Akishev, A. V. Dem’yanov, V. B. Karal’nik, A. E. Monich,

N. I. Trushkin, Plasma Phys. Rep. 2003, 29, 82.[25] M. Petit, A. Goldman, M. Goldman, J. Phys. D Appl. Phys. 2002,

35, 2969.[26] M. Laroussi, X. Lu, Appl. Phys. Lett. 2005, 87, 113902.[27] X. Li, P. Jia, N. Yuan, T. Fang, L. Wang, Phys. Plasmas 2011, 18,

043505.[28] D. B. Kim, J. K. Rhee, B. Gweon, S. Y. Moon, W. Choe, Appl. Phys.

Lett. 2007, 91, 151502.[29] S. Djurovic, J. R. Roberts, M. A. Sobolewski, J. K. Olthoff, J. Res.

Natl. Inst. Stand. Technol. 1993, 98, 159.[30] M. A. Naveed, A. Qayyum, S. Ali, M. Zakaullah, Phys. Lett. A

2006, 359, 499.[31] A. Qayyum, S. Zeb, S. Ali, A. Waheed, M. Zakaullah, Plasma

Chem. Plasma Process. 2005, 25, 551.[32] K. Shimizu, T. Ishii, M. Blajan, IEEE Trans. Ind. Appl. 2010, 46,

1125.

DOI: 10.1002/ppap.201100190

intense and energetic atmospheric pressure plasma jet arrays

Documents