Supporting Information Rapid growth of zinc oxide nanotube-nanowire ...
Supporting Information
Rapid growth of zinc oxide nanotube-nanowire hybrid architectures and their use in breast cancer-related volatile organics detection Giwan Katwal1, Maggie Paulose1, Irene A. Rusakova2, James E. Martinez3 and Oomman K. Varghese1* 1
Nanomaterials and Devices Laboratory, Department of Physics, University of Houston,
Houston, Texas 77204, USA. 2
Department of Physics and Texas Center for Superconductivity, University of Houston,
Houston, Texas 77204, USA. 3
Jacobs Technology, Structural Engineering, NASA Johnson Space Center, Houston, Texas
77058, USA.
*
515E Science & Research Building 1, University of Houston, Houston, Texas 77204, USA; (e-
mail) [email protected]; (phone) (1) 713 743-3808; (fax) (1) 713 743-3589
(b)
(a)
10 µm
10 µm
Figure S1: Low magnification SEM images showing the large area coverage of nanotubes in regions shown in Figure 1(b) and (c) are given in (a) and (b) respectively.
Intensity (a.u.)
Zn
O C 0
Zn Al P 2
4
6
8
10
Energy (keV) Figure S2 (a) The EDS element map and (b) corresponding spectrum from an as-prepared sample.
Figure S3: (a) TEM image of a nanotube and (b) the SAED singe crystal pattern showing the hexagonal phase of Zn(OH)2 structure.
Current (mA)
20
15
10
5
0
100 200 300 400 500 600 700
Time (s)
Figure S4: The variation of current with time during anodization.
Intensity (a.u.)
3000
1500
0 10
20
30
40
50
60
70
80
2θ (deg.)
Zn2P
3/2
5
0 0
C1s
Zn2s
Zn 2P O KLL
Zn 3p Zn 3s
ZnLMM3
400
ZnLLM2
5
1x10
Zn LMM1 ZnLMM O1s
1/2
2x10
O2s
Intensity (a.u.)
Figure S5: GAXRD pattern of the sample after 30 s of anodization. All the peaks can be indexed to hexagonal phase of zinc.
800
1200
Binding energy (eV)
Figure S6: XPS survey spectrum of an annealed sample.
Platinum contact ZnO nanotube/nano-rod
Figure S7: Schematic diagram of the sensor device.
Figure S8: Schematic diagram of sensor device characterization setup.
10000
Oxygen
2500
Intensity (a.u.)
Unexposed Exposed to VOC Purged with air
Unexposed Exposed to VOC Purged with air
8000
6000
4000
Zinc
280
285
290
525
295
Binding energy (eV)
Unexposed Exposed to VOC Purged with air
20000
5000
2000
1500
530
535
Binding energy (eV)
540
1018
1022
1026
Binding energy (eV)
Figure S9: XPS peaks of carbon, oxygen and zinc in case of sample unexposed, exposed to voc (100 ppm hetptanal) and purged with air after exposing. Annealed Air purged after voc VOC passed
50 40
Percentage
Intensity (a.u.)
Carbon
Intensity (a.u.)
3500
30 20 10 0
Zinc
Carbon
Oxygen
Figure S10: Bar graph showing percentage of zinc, carbon and oxygen in case of samples unexposed, exposed to VOC (100 ppm hetpanal) and exposed to VOC and then purged with air.
1030
100 Gold Platinum
VOC
R /R
Intensity (arb. units)
Zn
(a)
air
10
1
(b)
1000
1500
2000
O
400
Zn
Pt
0
500
0
In the electrode region In the region between electrodes
800
0
Time (s)
2
4
6
Energy (keV)
8
10
Figure S11: (a) Responses of the devices employing gold (red) or platinum (green) electrode to 100 ppm acetophenone. (b) Energy dispersive x-ray spectra of a sample used for gas sensing at 250 °C. Platinum peak can be seen in the spectrum (red) collected from the electrode region. No elements other than zinc and oxygen can be seen in the spectrum (green) from a region between the electrodes.
9
10 9
10
7
10
Dry Air + VOC 10
Humid air (RH ~90%) + VOC
Resistance (Ω)
Resistance (Ω)
8
10
(b)
VOC + Air
(a) 8
10
7
10
Air
6
0
500 1000 1500 2000 2500 3000 Time (s)
0
3
4 10
3
8 10
4
1.2 10
Time (s)
Figure S12: Plots showing (a) effect of humidity on the response (b) the operation of the devices when the ambient was switched between VOC diluted with air and pure air. 100 ppm acetophenone in air was used as the test gas.
Rapid growth of zinc oxide nanotube-nanowire hybrid architectures and their use in breast cancer-related volatile organics detection Giwan Katwal1, Maggie Paulose1, Irene A. Rusakova2, James E. Martinez3 and Oomman K. Varghese1* 1
Nanomaterials and Devices Laboratory, Department of Physics, University of Houston,
Houston, Texas 77204, USA. 2
Department of Physics and Texas Center for Superconductivity, University of Houston,
Houston, Texas 77204, USA. 3
Jacobs Technology, Structural Engineering, NASA Johnson Space Center, Houston, Texas
77058, USA.
*
515E Science & Research Building 1, University of Houston, Houston, Texas 77204, USA; (e-
mail) [email protected]; (phone) (1) 713 743-3808; (fax) (1) 713 743-3589
(b)
(a)
10 µm
10 µm
Figure S1: Low magnification SEM images showing the large area coverage of nanotubes in regions shown in Figure 1(b) and (c) are given in (a) and (b) respectively.
Intensity (a.u.)
Zn
O C 0
Zn Al P 2
4
6
8
10
Energy (keV) Figure S2 (a) The EDS element map and (b) corresponding spectrum from an as-prepared sample.
Figure S3: (a) TEM image of a nanotube and (b) the SAED singe crystal pattern showing the hexagonal phase of Zn(OH)2 structure.
Current (mA)
20
15
10
5
0
100 200 300 400 500 600 700
Time (s)
Figure S4: The variation of current with time during anodization.
Intensity (a.u.)
3000
1500
0 10
20
30
40
50
60
70
80
2θ (deg.)
Zn2P
3/2
5
0 0
C1s
Zn2s
Zn 2P O KLL
Zn 3p Zn 3s
ZnLMM3
400
ZnLLM2
5
1x10
Zn LMM1 ZnLMM O1s
1/2
2x10
O2s
Intensity (a.u.)
Figure S5: GAXRD pattern of the sample after 30 s of anodization. All the peaks can be indexed to hexagonal phase of zinc.
800
1200
Binding energy (eV)
Figure S6: XPS survey spectrum of an annealed sample.
Platinum contact ZnO nanotube/nano-rod
Figure S7: Schematic diagram of the sensor device.
Figure S8: Schematic diagram of sensor device characterization setup.
10000
Oxygen
2500
Intensity (a.u.)
Unexposed Exposed to VOC Purged with air
Unexposed Exposed to VOC Purged with air
8000
6000
4000
Zinc
280
285
290
525
295
Binding energy (eV)
Unexposed Exposed to VOC Purged with air
20000
5000
2000
1500
530
535
Binding energy (eV)
540
1018
1022
1026
Binding energy (eV)
Figure S9: XPS peaks of carbon, oxygen and zinc in case of sample unexposed, exposed to voc (100 ppm hetptanal) and purged with air after exposing. Annealed Air purged after voc VOC passed
50 40
Percentage
Intensity (a.u.)
Carbon
Intensity (a.u.)
3500
30 20 10 0
Zinc
Carbon
Oxygen
Figure S10: Bar graph showing percentage of zinc, carbon and oxygen in case of samples unexposed, exposed to VOC (100 ppm hetpanal) and exposed to VOC and then purged with air.
1030
100 Gold Platinum
VOC
R /R
Intensity (arb. units)
Zn
(a)
air
10
1
(b)
1000
1500
2000
O
400
Zn
Pt
0
500
0
In the electrode region In the region between electrodes
800
0
Time (s)
2
4
6
Energy (keV)
8
10
Figure S11: (a) Responses of the devices employing gold (red) or platinum (green) electrode to 100 ppm acetophenone. (b) Energy dispersive x-ray spectra of a sample used for gas sensing at 250 °C. Platinum peak can be seen in the spectrum (red) collected from the electrode region. No elements other than zinc and oxygen can be seen in the spectrum (green) from a region between the electrodes.
9
10 9
10
7
10
Dry Air + VOC 10
Humid air (RH ~90%) + VOC
Resistance (Ω)
Resistance (Ω)
8
10
(b)
VOC + Air
(a) 8
10
7
10
Air
6
0
500 1000 1500 2000 2500 3000 Time (s)
0
3
4 10
3
8 10
4
1.2 10
Time (s)
Figure S12: Plots showing (a) effect of humidity on the response (b) the operation of the devices when the ambient was switched between VOC diluted with air and pure air. 100 ppm acetophenone in air was used as the test gas.
