Delivered by Ingenta toNanyang Technological University
IP 1556944Sun 06 May 2012 040628
RESEARCH
ARTIC
LE
Copyright copy 2011 American Scientific PublishersAll rights reservedPrinted in the United States of America
Journal ofNanoscience and Nanotechnology
Vol 11 10706ndash10709 2011
Synthesis of BaCO3 Nanowires and TheirHumidity Sensitive Property
Hulin Zhang1 Chenguo Hu1lowast Michao Zhang1 Rusen Yang2 and Chunhua Zheng11Department of Applied Physics Chongqing University Chongqing 400044 China
2School of Materials Science and Engineering Georgia Institute of Technology Atlanta GA 30332 USA
Barium carbonate (BaCO3 nanowires have been synthesized for the first time by using the compos-ite hydroxide mediated (CHM) method The products are characterized by X-ray diffraction (XRD)field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy(TEM) Humidity sensors based on BaCO3 nanowires have been fabricated The response to humid-ity in static and dynamic measurement proves the ultrasensitive property of the sensors The resis-tance changes from 386 M to 71 M as the relative humidity (RH) increases from 20 to 95The response and recovery time of the resistance is 16 s and 56 s versus the changes of relativehumidity from 25 to 85 These results indicate promising applications of BaCO3 nanowires in ahighly sensitive environmental monitoring and humidity control electronic device
Keywords Barium Carbonate Nanowire Humidity
1 INTRODUCTION
Nanowires have been attracting great interest in the lastdecade Nanowires have exhibited superior electrical opti-cal mechanical and thermal properties and can be usedas fundamental building blocks for nano-scale science andtechnology ranging from chemical and biological sensorsfield effect transistors to logic circuits1ndash7 Barium carbon-ate exists in nature as a most thermodynamically stablecrystal modification among the heavy metal carbonates(ACO3 A Sr Pb and Ba)8 BaCO3 has also been exten-sively considered as an important material due to its closerelationship with aragonite biomineral its wide applica-tions in the ceramic and glass industries as well as itsuse as a precursor for magnetic ferrites and ferroelectricmaterials9 BaCO3 nanocrystals are commonly obtainedvia polymer induced synthesis routes10ndash14 Herein we takea new strategy to synthesize BaCO3 nanowires by the com-posite hydroxide mediated (CHM) method In additionHumidity sensors based on BaCO3 nanowires are fabri-cated and their sensitivity is investigated
2 EXPERIMENTAL DETAILS
NaF BaCl2 NaOH and KOH were purchased fromChongqing Chemical Reagent Company and all chemi-cals were of analytical grade and were used as received
lowastAuthor to whom correspondence should be addressed
Deionized water was used throughout BaCO3 nanowireswere prepared by the CHM approach Typically 00837 gNaF 0244 g BaCl2 and 9 g mixture of NaOH and KOHwith NaK ratio of 515485 were first put in a 25 mLTeflon vessel Second the vessel was placed in a furnacepreheated to 200 C for 30 minutes When the hydrox-ides were completely molten the vessel was taken out andshaken to mix the reactants uniformly Third the vesselwas put back in the furnace and incubated for 24 h Thevessel was then taken out and allowed to cool to room tem-perature Finally the product was washed with hot water(sim60 C) and dried at 80 CAn energy dispersive X-ray spectroscopy (EDS) and
X-ray diffractometer (XRD) with Cu K radiation(= 15418 Aring) at a 4min scanning speed from 10 to50 were used to investigate the crystal phase and chemicalcomposition The morphology and size of the synthesizedsample were characterized at 20 kV by a field emissionscanning electron microscopy (Nova 400 Nano SEM) andat 200 kV by a transmission electron microscopy (TEMHitachi HF-2000) The selected-area electron diffraction(SAED) pattern was taken on the TEMThin films for sensitive humidity sensors were prepared
from the BaCO3 nanowires as follows First the sampleswere dispersed in ethanol and then dropped on the sur-face of the Al2O3 substrate with two pairs of Ag inter-digital electrodes The dimensions of the films are 5 mmin length 3 mm in width and about 20 m in thickness
Delivered by Ingenta toNanyang Technological University
IP 1556944Sun 06 May 2012 040628
RESEARCH
ARTIC
LE
Zhang et al Synthesis of BaCO3 Nanowires and Their Humidity Sensitive Property
(from side view of SEM) Ohmic contacts for the pla-nar film consisted of copper wires and silver paste Theelectrode gap is about 02 mm The measurements werecarried out by putting the sensors in an airproof glass ves-sel with a volume of 2 L A hygroscope is placed in thevessel to monitor the humidity change during the experi-ment The sensorrsquos resistance was measured by a Keithley2400 Source Meter
3 RESULTS AND DISCUSSION
Figure 1 shows the morphology of the synthesized BaCO3
sample SEM and TEM images in Figures 1(andashc) illustratethe BaCO3 nanowires with diameters of 100ndash200 nm andlengths of 5ndash6 m The selected area electronic diffractionindicates that the nanowires are of single crystals EDS(inset Fig 1(a)) demonstrates that the composition of thesample are Ba C and O (Si signal is from the substrate)XRD spectrum shows that all the peaks are perfectlyindexed as an orthorhombic phase of BaCO3 (JCPDS-410373) with lattice constants of a = 6549 b = 5225c = 8834 Aring as shown in Figure 2
(c)
500 nm
100 nm
(d)
2 microm
(a) (b)
1 microm
Energy (keV)
O
Ba
C
Si
Fig 1 SEM images (a b) and EDS (inset a) and TEM image (c inset d) and SAED (d) of BaCO3 nanowires synthesized by the CHM method at200 C for 24 h
The possible reaction mechanism for the formation ofBaCO3 is proposed as follows NaOH and KOH play thesame role in the composite hydroxide melts To simplifythe expression for chemical reactions here we only includeNaOH in the formula
BaCl2 rarr Ba2++2Clminus (1)
NaOHrarr Na++OHminus (2)
Ba2++2OHminus rarr BaOH2 (3)
BaOH2+CO2 rarr BaCO3+H2O (4)
Reactions (1ndash3) happen in the composite hydroxidemelts in the Teflon vessel at 200 C while reaction (4)might occur after the product is removed from the vesselThe Ba(OH)2 obtained from step (3) reacts with CO2 inatmosphere to form BaCO3 thoroughly during the subse-quent washing and drying processTo explore its response to humidity we built a sensor
made from the BaCO3 nanowires (Fig 3(a)) The experi-mental setup is shown in Figure 3(b) with the humidity in
Delivered by Ingenta toNanyang Technological University
IP 1556944Sun 06 May 2012 040628
RESEARCH
ARTIC
LE
Synthesis of BaCO3 Nanowires and Their Humidity Sensitive Property Zhang et al
Fig 2 XRD of the BaCO3 nanowires All the XRD peaks are indexedby orthorhombic phase (JCPDS card 410373)
the test chamber regulated by a flow controller Figure 4(a)shows the sensitivity versus relative humidity (RH) in therange of 25ndash95 at 25 C Three plots represent threedifferent sensors made from the same BaCO3 nanowiresIt can be seen in these sensors that their resistance dropsrapidly as the humidity increases The change of resis-tance versus RH of these three sensors are similar and arealmost of two orders of magnitude as the RH increasesfrom 25 to 85 illustrating good reproducibility andexcellent humidity sensitivityIt is known that important parameters for sensor devices
are response time recovery time and reproducibility Toinvestigate these properties the dynamic testing of theBaCO3 nanowire device at a constant RH is performedThe response time for the sorption and desorption curvesmeasured at 25 C is shown in Figure 4(b) The responsetime from 25 to 85 RH is about 16 s while the recov-ery time from 85 to 25 RH is about 56 s Furthertesting after several additional cycles demonstrates goodreproducibility of the sensor The response and recoverytime of the BaCO3 nanowires sensors are much better thanthat of other sensors made from complex oxides15ndash17 andsimple oxides1819 Therefore the device made from the
R
Mixed air
Air out
Hygroscope
(b)
Glass vessel
(a)
Sample
Si substrate
SiO2
Au Au
Fig 3 Schematic sketches of sensor device (a) and humidity experi-ment setup (b)
20 30 40 50 60 70 80 90 100
0
20
40
60
80
100
Sen
sitiv
ity
RH
Sample 1Sample 2Sample 3
(a)
0 200 400 600 800 1000 12000
50
100
150
200
250
300
350
400
8585
2525
85
25
Res
ista
nce
(MΩ
)
Time (s)
(b)
Fig 4 Static (a) and dynamic (b) response of the device made ofBaCO3 nanowires Sensitivity= RRH minusR0R0times100 where R is resis-tance at 25RH
BaCO3 nanowires can be regarded as a superior responsehumidity sensorIn general there are two processes of adsorption of
water molecules2021 First the chemisorbing of a mono-layer of water with proton transfer among hydronium ions(H2O+H+ = H3O
+ and second the physisorbing of amultilayer of water with increasing humidity where bothH+ and H3O
+ act as charge carriers According to Ander-sonrsquos proton conductivity model22 when relative humidityis very low surface coverage of H2O is not complete andprotons can form and migrate by hopping from site to siteacross the surface When the surface is covered by waterproton transport is dominant which is confirmed by thecharacteristics of the resistance dependent on the relativehumidity in Figure 4(a) However the ionic conductivitybecomes dominant2324 when relative humidity is high Theshape of the nanowires facilitates the adsorption and des-orption of water molecules and results in fast response andrecovery to humidity25
4 CONCLUSIONS
BaCO3 nanowires have been synthesized for the firsttime by using the composite hydroxide mediated method
Delivered by Ingenta toNanyang Technological University
IP 1556944Sun 06 May 2012 040628
RESEARCH
ARTIC
LE
Zhang et al Synthesis of BaCO3 Nanowires and Their Humidity Sensitive Property
The nanowires are of single crystals with diameters of100ndash200 nm and lengths of 5ndash6 m and of orthorhom-bic phase The investigation of the humidity sensitivityof the sensors made from the BaCO3 nanowires revealsthat the shape of the nanowires facilitates the adsorp-tion and desorption of water molecules resulting in theirfast response and recovery to humidity BaCO3 nanowirescould be an excellent material for applications in highlysensitive environmental monitoring and humidity controlelectronic devices
Acknowledgments This work is supported by theNSFC (60976055) and Postgraduatesrsquo Science andInnovation Fund (201005B1A0010339) and InnovativeTraining Project (S-09109) of the 3rd-211 Project andthe large-scale equipment sharing fund of ChongqingUniversity
References and Notes
1 Z L Wang (ed) Nanowires and Nanobelts Kluwer Academic Pub-lishers Boston (2003) Vol 1ndash2
2 C Yang Z Zhong and C M Lieber Science 310 1304 (2005)3 C M Lieber and Z L Wang MRS Bull 32 99 (2007)4 X D Wang J H Song J Liu and Z L Wang Science 316 102
(2007)5 Z L Wang and J H Song Science 312 242 (2006)
6 Y J Dong B Z Tian T J Kempa and C M Lieber Nano Lett9 2183 (2009)
7 E C Garnett Y C Tseng D R Khanal J Q Wu J Bokor andP D Yang Nature Nanotechnol 4 311 (2009)
8 J S Xu and D F Xue J Phys Chem Solids 67 1427 (2006)9 B Gutmann and A Chalup Am Ceram Soc Bull 72 83 (1993)10 Sondi and E Matijevieacute Chem Mater 15 1322 (2003)11 S Yu H Cooumllfen A Xu and W Dong Cryst Growth Des 4 33
(2004)12 S Yu H Coumllfen K Tauer and M Antonietti Nat Mater 4 51
(2005)13 W Li S T Sun Q S Yu and P Y Wu Cryst Growth Des
10 2685 (2010)14 L Qi J Ma H Cheng and Z Zhao J Phys Chem B 101 3460
(1997)15 M H Zhou and A Ahmad Sens Actuators B 129 285 (2008)16 S Upadhyay and P Kavitha Mater Lett 61 1912 (2007)17 K S Nagaraja J J Vijaya L J Kennedy and G Sekaran Sens
Actuators B 124 542 (2007)18 N Zhang K Yu Z Q Zhu and D S Jiang Sens Actuators A
143 245 (2008)19 Y Y Zhang W Y Fu H B Yang Q Qi Y Zeng T Zhang R X
Ge and G Zou Appl Surf Sci 254 5545 (2008)20 K S Chou T K Lee and F J Liu Sens Actuators B 56 106
(1999)21 Z Chen and C Lu Sensor Lett 3 274 (2005)22 J H Anderson and G A Parks J Phys Chem 72 3662 (1968)23 B M Kulwicki J Phys Chem Solids 45 1015 (1984)24 C Y Lee and G B Lee Sensor Lett 3 1 (2005)25 X Q Fu C Wang H C Yu Y G Wang and T H Wang Nano-
technology 18 145503 (2007)
Received 30 December 2009 RevisedAccepted 30 August 2010
Delivered by Ingenta toNanyang Technological University
IP 1556944Sun 06 May 2012 040628
RESEARCH
ARTIC
LE
Zhang et al Synthesis of BaCO3 Nanowires and Their Humidity Sensitive Property
(from side view of SEM) Ohmic contacts for the pla-nar film consisted of copper wires and silver paste Theelectrode gap is about 02 mm The measurements werecarried out by putting the sensors in an airproof glass ves-sel with a volume of 2 L A hygroscope is placed in thevessel to monitor the humidity change during the experi-ment The sensorrsquos resistance was measured by a Keithley2400 Source Meter
3 RESULTS AND DISCUSSION
Figure 1 shows the morphology of the synthesized BaCO3
sample SEM and TEM images in Figures 1(andashc) illustratethe BaCO3 nanowires with diameters of 100ndash200 nm andlengths of 5ndash6 m The selected area electronic diffractionindicates that the nanowires are of single crystals EDS(inset Fig 1(a)) demonstrates that the composition of thesample are Ba C and O (Si signal is from the substrate)XRD spectrum shows that all the peaks are perfectlyindexed as an orthorhombic phase of BaCO3 (JCPDS-410373) with lattice constants of a = 6549 b = 5225c = 8834 Aring as shown in Figure 2
(c)
500 nm
100 nm
(d)
2 microm
(a) (b)
1 microm
Energy (keV)
O
Ba
C
Si
Fig 1 SEM images (a b) and EDS (inset a) and TEM image (c inset d) and SAED (d) of BaCO3 nanowires synthesized by the CHM method at200 C for 24 h
The possible reaction mechanism for the formation ofBaCO3 is proposed as follows NaOH and KOH play thesame role in the composite hydroxide melts To simplifythe expression for chemical reactions here we only includeNaOH in the formula
BaCl2 rarr Ba2++2Clminus (1)
NaOHrarr Na++OHminus (2)
Ba2++2OHminus rarr BaOH2 (3)
BaOH2+CO2 rarr BaCO3+H2O (4)
Reactions (1ndash3) happen in the composite hydroxidemelts in the Teflon vessel at 200 C while reaction (4)might occur after the product is removed from the vesselThe Ba(OH)2 obtained from step (3) reacts with CO2 inatmosphere to form BaCO3 thoroughly during the subse-quent washing and drying processTo explore its response to humidity we built a sensor
made from the BaCO3 nanowires (Fig 3(a)) The experi-mental setup is shown in Figure 3(b) with the humidity in
Delivered by Ingenta toNanyang Technological University
IP 1556944Sun 06 May 2012 040628
RESEARCH
ARTIC
LE
Synthesis of BaCO3 Nanowires and Their Humidity Sensitive Property Zhang et al
Fig 2 XRD of the BaCO3 nanowires All the XRD peaks are indexedby orthorhombic phase (JCPDS card 410373)
the test chamber regulated by a flow controller Figure 4(a)shows the sensitivity versus relative humidity (RH) in therange of 25ndash95 at 25 C Three plots represent threedifferent sensors made from the same BaCO3 nanowiresIt can be seen in these sensors that their resistance dropsrapidly as the humidity increases The change of resis-tance versus RH of these three sensors are similar and arealmost of two orders of magnitude as the RH increasesfrom 25 to 85 illustrating good reproducibility andexcellent humidity sensitivityIt is known that important parameters for sensor devices
are response time recovery time and reproducibility Toinvestigate these properties the dynamic testing of theBaCO3 nanowire device at a constant RH is performedThe response time for the sorption and desorption curvesmeasured at 25 C is shown in Figure 4(b) The responsetime from 25 to 85 RH is about 16 s while the recov-ery time from 85 to 25 RH is about 56 s Furthertesting after several additional cycles demonstrates goodreproducibility of the sensor The response and recoverytime of the BaCO3 nanowires sensors are much better thanthat of other sensors made from complex oxides15ndash17 andsimple oxides1819 Therefore the device made from the
R
Mixed air
Air out
Hygroscope
(b)
Glass vessel
(a)
Sample
Si substrate
SiO2
Au Au
Fig 3 Schematic sketches of sensor device (a) and humidity experi-ment setup (b)
20 30 40 50 60 70 80 90 100
0
20
40
60
80
100
Sen
sitiv
ity
RH
Sample 1Sample 2Sample 3
(a)
0 200 400 600 800 1000 12000
50
100
150
200
250
300
350
400
8585
2525
85
25
Res
ista
nce
(MΩ
)
Time (s)
(b)
Fig 4 Static (a) and dynamic (b) response of the device made ofBaCO3 nanowires Sensitivity= RRH minusR0R0times100 where R is resis-tance at 25RH
BaCO3 nanowires can be regarded as a superior responsehumidity sensorIn general there are two processes of adsorption of
water molecules2021 First the chemisorbing of a mono-layer of water with proton transfer among hydronium ions(H2O+H+ = H3O
+ and second the physisorbing of amultilayer of water with increasing humidity where bothH+ and H3O
+ act as charge carriers According to Ander-sonrsquos proton conductivity model22 when relative humidityis very low surface coverage of H2O is not complete andprotons can form and migrate by hopping from site to siteacross the surface When the surface is covered by waterproton transport is dominant which is confirmed by thecharacteristics of the resistance dependent on the relativehumidity in Figure 4(a) However the ionic conductivitybecomes dominant2324 when relative humidity is high Theshape of the nanowires facilitates the adsorption and des-orption of water molecules and results in fast response andrecovery to humidity25
4 CONCLUSIONS
BaCO3 nanowires have been synthesized for the firsttime by using the composite hydroxide mediated method
Delivered by Ingenta toNanyang Technological University
IP 1556944Sun 06 May 2012 040628
RESEARCH
ARTIC
LE
Zhang et al Synthesis of BaCO3 Nanowires and Their Humidity Sensitive Property
The nanowires are of single crystals with diameters of100ndash200 nm and lengths of 5ndash6 m and of orthorhom-bic phase The investigation of the humidity sensitivityof the sensors made from the BaCO3 nanowires revealsthat the shape of the nanowires facilitates the adsorp-tion and desorption of water molecules resulting in theirfast response and recovery to humidity BaCO3 nanowirescould be an excellent material for applications in highlysensitive environmental monitoring and humidity controlelectronic devices
Acknowledgments This work is supported by theNSFC (60976055) and Postgraduatesrsquo Science andInnovation Fund (201005B1A0010339) and InnovativeTraining Project (S-09109) of the 3rd-211 Project andthe large-scale equipment sharing fund of ChongqingUniversity
References and Notes
1 Z L Wang (ed) Nanowires and Nanobelts Kluwer Academic Pub-lishers Boston (2003) Vol 1ndash2
2 C Yang Z Zhong and C M Lieber Science 310 1304 (2005)3 C M Lieber and Z L Wang MRS Bull 32 99 (2007)4 X D Wang J H Song J Liu and Z L Wang Science 316 102
(2007)5 Z L Wang and J H Song Science 312 242 (2006)
6 Y J Dong B Z Tian T J Kempa and C M Lieber Nano Lett9 2183 (2009)
7 E C Garnett Y C Tseng D R Khanal J Q Wu J Bokor andP D Yang Nature Nanotechnol 4 311 (2009)
8 J S Xu and D F Xue J Phys Chem Solids 67 1427 (2006)9 B Gutmann and A Chalup Am Ceram Soc Bull 72 83 (1993)10 Sondi and E Matijevieacute Chem Mater 15 1322 (2003)11 S Yu H Cooumllfen A Xu and W Dong Cryst Growth Des 4 33
(2004)12 S Yu H Coumllfen K Tauer and M Antonietti Nat Mater 4 51
(2005)13 W Li S T Sun Q S Yu and P Y Wu Cryst Growth Des
10 2685 (2010)14 L Qi J Ma H Cheng and Z Zhao J Phys Chem B 101 3460
(1997)15 M H Zhou and A Ahmad Sens Actuators B 129 285 (2008)16 S Upadhyay and P Kavitha Mater Lett 61 1912 (2007)17 K S Nagaraja J J Vijaya L J Kennedy and G Sekaran Sens
Actuators B 124 542 (2007)18 N Zhang K Yu Z Q Zhu and D S Jiang Sens Actuators A
143 245 (2008)19 Y Y Zhang W Y Fu H B Yang Q Qi Y Zeng T Zhang R X
Ge and G Zou Appl Surf Sci 254 5545 (2008)20 K S Chou T K Lee and F J Liu Sens Actuators B 56 106
(1999)21 Z Chen and C Lu Sensor Lett 3 274 (2005)22 J H Anderson and G A Parks J Phys Chem 72 3662 (1968)23 B M Kulwicki J Phys Chem Solids 45 1015 (1984)24 C Y Lee and G B Lee Sensor Lett 3 1 (2005)25 X Q Fu C Wang H C Yu Y G Wang and T H Wang Nano-
technology 18 145503 (2007)
Received 30 December 2009 RevisedAccepted 30 August 2010
Delivered by Ingenta toNanyang Technological University
IP 1556944Sun 06 May 2012 040628
RESEARCH
ARTIC
LE
Synthesis of BaCO3 Nanowires and Their Humidity Sensitive Property Zhang et al
Fig 2 XRD of the BaCO3 nanowires All the XRD peaks are indexedby orthorhombic phase (JCPDS card 410373)
the test chamber regulated by a flow controller Figure 4(a)shows the sensitivity versus relative humidity (RH) in therange of 25ndash95 at 25 C Three plots represent threedifferent sensors made from the same BaCO3 nanowiresIt can be seen in these sensors that their resistance dropsrapidly as the humidity increases The change of resis-tance versus RH of these three sensors are similar and arealmost of two orders of magnitude as the RH increasesfrom 25 to 85 illustrating good reproducibility andexcellent humidity sensitivityIt is known that important parameters for sensor devices
are response time recovery time and reproducibility Toinvestigate these properties the dynamic testing of theBaCO3 nanowire device at a constant RH is performedThe response time for the sorption and desorption curvesmeasured at 25 C is shown in Figure 4(b) The responsetime from 25 to 85 RH is about 16 s while the recov-ery time from 85 to 25 RH is about 56 s Furthertesting after several additional cycles demonstrates goodreproducibility of the sensor The response and recoverytime of the BaCO3 nanowires sensors are much better thanthat of other sensors made from complex oxides15ndash17 andsimple oxides1819 Therefore the device made from the
R
Mixed air
Air out
Hygroscope
(b)
Glass vessel
(a)
Sample
Si substrate
SiO2
Au Au
Fig 3 Schematic sketches of sensor device (a) and humidity experi-ment setup (b)
20 30 40 50 60 70 80 90 100
0
20
40
60
80
100
Sen
sitiv
ity
RH
Sample 1Sample 2Sample 3
(a)
0 200 400 600 800 1000 12000
50
100
150
200
250
300
350
400
8585
2525
85
25
Res
ista
nce
(MΩ
)
Time (s)
(b)
Fig 4 Static (a) and dynamic (b) response of the device made ofBaCO3 nanowires Sensitivity= RRH minusR0R0times100 where R is resis-tance at 25RH
BaCO3 nanowires can be regarded as a superior responsehumidity sensorIn general there are two processes of adsorption of
water molecules2021 First the chemisorbing of a mono-layer of water with proton transfer among hydronium ions(H2O+H+ = H3O
+ and second the physisorbing of amultilayer of water with increasing humidity where bothH+ and H3O
+ act as charge carriers According to Ander-sonrsquos proton conductivity model22 when relative humidityis very low surface coverage of H2O is not complete andprotons can form and migrate by hopping from site to siteacross the surface When the surface is covered by waterproton transport is dominant which is confirmed by thecharacteristics of the resistance dependent on the relativehumidity in Figure 4(a) However the ionic conductivitybecomes dominant2324 when relative humidity is high Theshape of the nanowires facilitates the adsorption and des-orption of water molecules and results in fast response andrecovery to humidity25
4 CONCLUSIONS
BaCO3 nanowires have been synthesized for the firsttime by using the composite hydroxide mediated method
Delivered by Ingenta toNanyang Technological University
IP 1556944Sun 06 May 2012 040628
RESEARCH
ARTIC
LE
Zhang et al Synthesis of BaCO3 Nanowires and Their Humidity Sensitive Property
The nanowires are of single crystals with diameters of100ndash200 nm and lengths of 5ndash6 m and of orthorhom-bic phase The investigation of the humidity sensitivityof the sensors made from the BaCO3 nanowires revealsthat the shape of the nanowires facilitates the adsorp-tion and desorption of water molecules resulting in theirfast response and recovery to humidity BaCO3 nanowirescould be an excellent material for applications in highlysensitive environmental monitoring and humidity controlelectronic devices
Acknowledgments This work is supported by theNSFC (60976055) and Postgraduatesrsquo Science andInnovation Fund (201005B1A0010339) and InnovativeTraining Project (S-09109) of the 3rd-211 Project andthe large-scale equipment sharing fund of ChongqingUniversity
References and Notes
1 Z L Wang (ed) Nanowires and Nanobelts Kluwer Academic Pub-lishers Boston (2003) Vol 1ndash2
2 C Yang Z Zhong and C M Lieber Science 310 1304 (2005)3 C M Lieber and Z L Wang MRS Bull 32 99 (2007)4 X D Wang J H Song J Liu and Z L Wang Science 316 102
(2007)5 Z L Wang and J H Song Science 312 242 (2006)
6 Y J Dong B Z Tian T J Kempa and C M Lieber Nano Lett9 2183 (2009)
7 E C Garnett Y C Tseng D R Khanal J Q Wu J Bokor andP D Yang Nature Nanotechnol 4 311 (2009)
8 J S Xu and D F Xue J Phys Chem Solids 67 1427 (2006)9 B Gutmann and A Chalup Am Ceram Soc Bull 72 83 (1993)10 Sondi and E Matijevieacute Chem Mater 15 1322 (2003)11 S Yu H Cooumllfen A Xu and W Dong Cryst Growth Des 4 33
(2004)12 S Yu H Coumllfen K Tauer and M Antonietti Nat Mater 4 51
(2005)13 W Li S T Sun Q S Yu and P Y Wu Cryst Growth Des
10 2685 (2010)14 L Qi J Ma H Cheng and Z Zhao J Phys Chem B 101 3460
(1997)15 M H Zhou and A Ahmad Sens Actuators B 129 285 (2008)16 S Upadhyay and P Kavitha Mater Lett 61 1912 (2007)17 K S Nagaraja J J Vijaya L J Kennedy and G Sekaran Sens
Actuators B 124 542 (2007)18 N Zhang K Yu Z Q Zhu and D S Jiang Sens Actuators A
143 245 (2008)19 Y Y Zhang W Y Fu H B Yang Q Qi Y Zeng T Zhang R X
Ge and G Zou Appl Surf Sci 254 5545 (2008)20 K S Chou T K Lee and F J Liu Sens Actuators B 56 106
(1999)21 Z Chen and C Lu Sensor Lett 3 274 (2005)22 J H Anderson and G A Parks J Phys Chem 72 3662 (1968)23 B M Kulwicki J Phys Chem Solids 45 1015 (1984)24 C Y Lee and G B Lee Sensor Lett 3 1 (2005)25 X Q Fu C Wang H C Yu Y G Wang and T H Wang Nano-
technology 18 145503 (2007)
Received 30 December 2009 RevisedAccepted 30 August 2010
Delivered by Ingenta toNanyang Technological University
IP 1556944Sun 06 May 2012 040628
RESEARCH
ARTIC
LE
Zhang et al Synthesis of BaCO3 Nanowires and Their Humidity Sensitive Property
The nanowires are of single crystals with diameters of100ndash200 nm and lengths of 5ndash6 m and of orthorhom-bic phase The investigation of the humidity sensitivityof the sensors made from the BaCO3 nanowires revealsthat the shape of the nanowires facilitates the adsorp-tion and desorption of water molecules resulting in theirfast response and recovery to humidity BaCO3 nanowirescould be an excellent material for applications in highlysensitive environmental monitoring and humidity controlelectronic devices
Acknowledgments This work is supported by theNSFC (60976055) and Postgraduatesrsquo Science andInnovation Fund (201005B1A0010339) and InnovativeTraining Project (S-09109) of the 3rd-211 Project andthe large-scale equipment sharing fund of ChongqingUniversity
References and Notes
1 Z L Wang (ed) Nanowires and Nanobelts Kluwer Academic Pub-lishers Boston (2003) Vol 1ndash2
2 C Yang Z Zhong and C M Lieber Science 310 1304 (2005)3 C M Lieber and Z L Wang MRS Bull 32 99 (2007)4 X D Wang J H Song J Liu and Z L Wang Science 316 102
(2007)5 Z L Wang and J H Song Science 312 242 (2006)
6 Y J Dong B Z Tian T J Kempa and C M Lieber Nano Lett9 2183 (2009)
7 E C Garnett Y C Tseng D R Khanal J Q Wu J Bokor andP D Yang Nature Nanotechnol 4 311 (2009)
8 J S Xu and D F Xue J Phys Chem Solids 67 1427 (2006)9 B Gutmann and A Chalup Am Ceram Soc Bull 72 83 (1993)10 Sondi and E Matijevieacute Chem Mater 15 1322 (2003)11 S Yu H Cooumllfen A Xu and W Dong Cryst Growth Des 4 33
(2004)12 S Yu H Coumllfen K Tauer and M Antonietti Nat Mater 4 51
(2005)13 W Li S T Sun Q S Yu and P Y Wu Cryst Growth Des
10 2685 (2010)14 L Qi J Ma H Cheng and Z Zhao J Phys Chem B 101 3460
(1997)15 M H Zhou and A Ahmad Sens Actuators B 129 285 (2008)16 S Upadhyay and P Kavitha Mater Lett 61 1912 (2007)17 K S Nagaraja J J Vijaya L J Kennedy and G Sekaran Sens
Actuators B 124 542 (2007)18 N Zhang K Yu Z Q Zhu and D S Jiang Sens Actuators A
143 245 (2008)19 Y Y Zhang W Y Fu H B Yang Q Qi Y Zeng T Zhang R X
Ge and G Zou Appl Surf Sci 254 5545 (2008)20 K S Chou T K Lee and F J Liu Sens Actuators B 56 106
(1999)21 Z Chen and C Lu Sensor Lett 3 274 (2005)22 J H Anderson and G A Parks J Phys Chem 72 3662 (1968)23 B M Kulwicki J Phys Chem Solids 45 1015 (1984)24 C Y Lee and G B Lee Sensor Lett 3 1 (2005)25 X Q Fu C Wang H C Yu Y G Wang and T H Wang Nano-
technology 18 145503 (2007)
Received 30 December 2009 RevisedAccepted 30 August 2010
