OSA's Digital Library

Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 19, Iss. 27 — Dec. 19, 2011
  • pp: 26006–26010

Optics InfoBase > Optics Express > Volume 19 > Issue 27 > Page 26006

« Show journal navigation

Nanostructured n-ZnO / thin film p-silicon heterojunction light-emitting diodes

Jaehui Ahn, Hyunik Park, Michael A. Mastro, Jennifer K. Hite, Charles R. Eddy, and Jihyun Kim  »View Author Affiliations


Optics Express, Vol. 19, Issue 27, pp. 26006-26010 (2011)
http://dx.doi.org/10.1364/OE.19.026006


View Full Text Article

Acrobat PDF (856 KB)


Advanced Search

Browse Journals / Lookup Meetings

Browse by Journal and Year


   


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools

Share
Citations

Abstract

Electroluminescence (EL) was obtained from a p-Si (100) thin film / nanostructured n-ZnO heterojunction diode fabricated by a simple dielectrophoresis (DEP) method. The Si substrate was pre-patterned with electrodes and an insulating separation layer by a standard photolithographic process. ZnO nanostructures were formed by a simple solution chemistry and subsequently transferred to the pre-patterned substrate. Application of the DEP force at a frequency of 100 kHz and 6 V peak-to-peak voltage allowed precise positioning of the ZnO nanostructures at the edge of the metal electrodes. The physically formed p-Si (100) thin film/ nanostructured n-ZnO heterojunction displayed multi-color emission from the ZnO near band edge as well as emission from defective states within the ZnO band gap.

© 2011 OSA

1. Introduction

Nanostructured electronics and optoelectronics are often motivated based on the materials with low defect density, natural faceting, large surface-to-volume ratio, and extremely small size [1

Y. Li, F. Qian, J. Xiang, and C. M. Lieber, “Nanowire electronic and optoelectronic devices,” Mater. Today 9(10), 18–27 (2006). [CrossRef]

–3

D. Lucot, F. Jabeen, J.-C. Harmand, G. Patriarche, R. Giraud, G. Faini, and D. Mailly, “Quasi one-dimensional transport in single GaAs/AlGaAs core-shell nanowires,” Appl. Phys. Lett. 98(14), 142114 (2011). [CrossRef]

]. Bottom-up formation of nanoscale light emitter arguably can simplify the fabrication of integrated-optoelectronics and optical interconnection [4

A. Motayed, A. V. Davydov, M. He, S. N. Mohammad, and J. Melngailis, “365 nm operation of n-nanowire/p-gallium nitride homojunction light emitting diodes,” Appl. Phys. Lett. 90(18), 183120 (2007). [CrossRef]

–8

T. Kuykendall, P. Ulrich, S. Aloni, and P. Yang, “Complete composition tunability of InGaN nanowires using a combinatorial approach,” Nat. Mater. 6(12), 951–956 (2007). [CrossRef] [PubMed]

]. Despite these advantages, bottom-up formation of nanoscale devices has not been widely introduced into the semiconductor industry. This is particularly true in the silicon microelectronics industry where the planar morphology is well suited to top-down lithography and depostion.

In contrast, research into nanoscale devices is highly reliant on bottom-up techniques particularly electron-beam lithography (EBL) and focused-ion beam (FIB) [9

F. Qian, S. Gradečak, Y. Li, C.-Y. Wen, and C. M. Lieber, “Core/multishell nanowire heterostructures as multicolor, high-efficiency light-emitting diodes,” Nano Lett. 5(11), 2287–2291 (2005). [CrossRef] [PubMed]

, 10

B. Prével, J.-M. Benoit, L. Bardotti, P. Mélinon, A. Ouerghi, D. Lucot, E. Bourhis, and J. Gierak, “Nanostructuring graphene on SiC by focused ion beam: effect of the ion fluence,” Appl. Phys. Lett. 99(8), 083116 (2011). [CrossRef]

]. The EBL and FIB approaches employ a laborious one-by-one formation and are not suited for scale-up to mass-production. Additionally, EBL and FIB have no capability to position or align randomly dispersed nanostructures, which is one of the issues in nanofabrication. Fluidic mechanics and transfer methods have been investigated as an alternative to resolve these issues associated with the random positioning of nanostructures [11

D. Kim, Y.-K. Kim, S. C. Park, J. S. Ha, J. Huh, J. Na, and G.-T. Kim, “Photoconductance of aligned SnO2 nanowire field effect transistors,” Appl. Phys. Lett. 95(4), 043107 (2009). [CrossRef]

, 12

X. Chen, G. Cao, A. Han, V. K. Punyamurtula, L. Liu, P. J. Culligan, T. Kim, and Y. Qiao, “Nanoscale fluid transport: size and rate effects,” Nano Lett. 8(9), 2988–2992 (2008). [CrossRef] [PubMed]

]. Alignment of nanostructures using fluidic mechanics has the advantage of precise control but this process increases in complexity for alignment of multiple nanowires (NWs). In contrast, the transfer method is a very simple process but precise position control is difficult to be achieved.

The authors previously used the DEP force to manipulate the position of nanoscale semiconductors onto semiconductor thin films (including a homojunction consisting of n-GaN NWs on p-GaN thin-film as well as a heterojunction composed of nanostructured n-ZnO on p-GaN thin film) [13

J. Ahn, M. A. Mastro, J. Hite, C. R. Eddy Jr, and J. Kim, “Violet electroluminescence from p-GaN thin film/n-GaN nanowire homojunction,” Appl. Phys. Lett. 96(13), 132105 (2010). [CrossRef]

, 14

J. Ahn, M. A. Mastro, J. Hite, C. R. Eddy Jr, and J. Kim, “Electroluminescence from ZnO nanoflowers/GaN thin film p-n heterojunction,” Appl. Phys. Lett. 97(8), 082111 (2010). [CrossRef]

]. The DEP force involves applying a force to a dielectric particle under an irregular electric field [15

H. A. Pohl, Dielectrophoresis (Cambridge University Press, 1978).

]. This method was first developed and used by Herbert Pohl in the 1950s and has since been widely used to separate biomaterials or particles on the nano/micro scale [16

G. H. Markx, M. S. Talary, and R. Pethig, “Separation of viable and non-viable yeast using dielectrophoresis,” J. Biotechnol. 32(1), 29–37 (1994). [CrossRef] [PubMed]

]. More recently, the DEP force has been used for nano-fabrication of semiconductor structures [17

B. R. Burg and D. Poulikakos, “Large-scale integration of single-walled carbon nanotubes and graphene into sensors and devices using dielectrophoresis: a review,” J. Mater. Res. 26(13), 1561–1571 (2011). [CrossRef]

, 18

T. H. Kim, S. Y. Lee, N. K. Cho, H. K. Seong, H. J. Choi, S. W. Jung, and S. K. Lee, “Dielectrophoretic alignment of gallium nitride nanowires (GaN NWs) for use in device applications,” Nanotechnology 17(14), 3394–3399 (2006). [CrossRef] [PubMed]

]. The precision positioning by the DEP force allows extension of the DEP method to a number of areas including potentially silicon microelectronics industry.

In the study, p-n heterojunction LEDs were physically formed from nanostructured n-type ZnO on a p-Si substrate. The physically formed junction conducted current and emitted light similar to a p-n junction formed by epitaxy or other comparable process. ZnO is advantageous as it has a large binding energy of excitons and direct band gap, which leads to an effective emission [19

J. Aranovich, A. Ortiz, and R. H. Bube, “Optical and electrical properties of ZnO films prepared by spray pyrolysis for solar cell applications,” J. Vac. Sci. Technol. 16(4), 994 (1979). [CrossRef]

, 20

X. W. Sun, J. Z. Huang, J. X. Wang, and Z. Xu, “A ZnO nanorod inorganic/organic heterostructure light-emitting diode emitting at 342 nm,” Nano Lett. 8(4), 1219–1223 (2008). [CrossRef] [PubMed]

]. Furthermore, large quantities of ZnO nanostructures can be rapidly and simply produced by one of several low-cost solution processes. Silicon is a relatively low-cost semiconductor substrate, and the technology for selective area fabrication of electrodes and insulating oxides on Si substrates has been well established by the silicon industry. This work shows that the application of ZnO nanostructures onto a Si substrate and positioning via the DEP method is an undemanding and low cost technique to form a nano-sized light emitter, which has potential applications in nano-optoelectronics.

2. Experimental details

In this study, a p-n junction was fabricated by precisely positioning n-ZnO nanostructures on a pre-patterned p-Si substrate with oxide mesa and metal electrodes. Prior to the ZnO growth, glass slides were washed in methanol and deionized water. The ZnO nanostructures were deposited on glass slides in a solution of 5 mL zinc acetate in water (0.001 M), 10 mL NaOH in water (0.01 M), and 1 mL ethylene glycol at 130°C in a covered Teflon beaker. Deposition on glass slides was selected as a convenient host for transport and is not central to the main thesis of this paper. Cathodoluminescence (CL, MonoCL, Gatan Co.) data was obtained from the grown ZnO nanostructures. The morphology of the ZnO nanostructures was characterized by scanning electron microscopy (SEM, S-4700, Hitachi Co.).

A 300 nm SiO2 layer was thermally grown on a p + Si substrate (Boron-doped, 1.0~10.0 ohm•cm), followed by using a buffered oxide etchant (BOE) solution to remove the backside SiO2 with a front protected. Circular electrodes were patterned on top of a SiO2 layer by standard photolithographic process, followed by Ti/Au (20/80 nm) deposition using an e-beam evaporation process. After the lift-off process, reactive ion etching (RIE, SN Tek Co.) was performed in 10 sccm O2 and 10 sccm SF6 at 100 watt, followed by BOE etching to remove any residual SiO2. The ZnO nanostructures were dispersed in an iso-propyl alcohol solution and dropped onto the pre-patterned Si substrate. The DEP force was generated by employing a function generator (33250A 80 MHz Function/Arbitrary Waveform Generator, Agilent) at an amplitude of 6 peak-to-peak voltage at 100 kHz to manipulate the ZnO nanostructures. After drying, the current-voltage (I-V) characteristics were obtained with an Agilent 4155C Parameter Analyzer. EL was recorded at a forward bias of 10 V with the images and video obtained via a charge-coupled devices (CCD) camera attached to the probe-station.

3. Results and discussion

A schematic of the thin film p-Si / nanostuctured n-ZnO heterojunction LED is displayed in Fig. 1(a) . The electron micrograph in Fig. 1(b) confirms that the ZnO nanostructures were attracted by DEP force to the correct position at the edge of the metal electrodes. Additionally, Fig. 1(b) and 2(b) reveals a desired undercut between the Ti/Au electrode and Si thin film. The ZnO nanostructures were manipulated by the non-uniform electric field around the electrode. Under the non-uniform electric field, the DEP force on a dielectric particle is calculated by vector calculation: F = p∙∇E, where p is the induced dipole moment, E the electric field. If the direction of the dipole moment is not parallel to the electric field, the dielectric particle will be rotated by the torque. Quasi one-dimensional nanostructures such as nanowires and nanorods with high aspect ratios are more easily aligned along the electric field compared with the spherical particles. Torque played a vital role in the alignment of the rod shaped nanostructures, where the torque (T) is given by vector T = p × E, which will disappear once the axis of nanostructure is aligned to be parallel to the direction of the electric field. Figure 2(b) shows that the ZnO nanorods are aligned parallel to the electric field. Figure 2(a) shows the CL data of the ZnO nanostructures. The CL spectrum of ZnO nanostructures displayed near-UV band edge emission at a peak of 381 nm, which is consistent with the band gap of ZnO [19

J. Aranovich, A. Ortiz, and R. H. Bube, “Optical and electrical properties of ZnO films prepared by spray pyrolysis for solar cell applications,” J. Vac. Sci. Technol. 16(4), 994 (1979). [CrossRef]

].

Fig. 1 (a) Schematic and (b) SEM images of the p-Si thin film / n-ZnO nanoflower structure. The scale bar in the SEM image is 1μm.
Fig. 2 (a) CL spectrum of the nanostructured ZnO (b) SEM image confirms that the ZnO nanostructures aligned parallel to the electric field after DEP process. The scale bar in the SEM image is 1μm.

After the ZnO nanostructures were positioned by the DEP process, the I-V characteristics were measured without additional thermal annealing treatment. The device displayed current conduction in a manner characteristic of functional p-n junction from physical contact between the p-Si thin film / n-ZnO nanostructures (Fig. 3(a) ). The I-V curve of the p-Si thin film / n-ZnO nanostructures heterojunction LED displayed a turn-on voltage near 3V. This onset of forward conduction occurred when the forward bias is larger than the band gap of Si. At this point, the electrons in the conduction band of ZnO move into the conduction band of Si, which initiates a low level current flow [20

X. W. Sun, J. Z. Huang, J. X. Wang, and Z. Xu, “A ZnO nanorod inorganic/organic heterostructure light-emitting diode emitting at 342 nm,” Nano Lett. 8(4), 1219–1223 (2008). [CrossRef] [PubMed]

, 21

K. Kim, J. Kang, M. Lee, C. Yoon, K. Cho, and S. Kim, “Ultraviolet electroluminescence emission from n-type ZnO/p-type Si crossed nanowire light-emitting diodes,” Jpn. J. Appl. Phys. 49(6), 06GG05 (2010). [CrossRef]

]. The electron affinity and band gap were 4.05 and 1.1eV, respectively, for Si and the electron affinity and band gap of ZnO were 4.35 and 3.3eV, respectively [22

S. M. Sze, Physics of Semiconductor Devices (Wiley, 2007).

, 23

J. A. Aranovich, D. Golmayo, A. L. Fahrenbruch, and R. H. Bube, “Photovoltaic properties of ZnO/CdTe heterojunctions prepared by spray pyrolysis,” J. Appl. Phys. 51(8), 4260–4268 (1980). [CrossRef]

]. The forward bias of 2~3V was approximately the energy needed to align the conduction band of ZnO and Si. When the forward bias was larger than approximately the bandgap of ZnO, major conduction initiated as the holes in the valence band of p-Si possessed sufficient energy to surmount the valence band discontinuity and flow into the valence band of ZnO (Fig. 3(b)). Although the band gap of ZnO was 3.3eV, the delayed onset of major conduction near 4V can be attributed to the presence of a thin oxide layer or nanoscale roughness at the mechanical contact between n-ZnO nanostructures and p-Si thin film. The band diagram of the nanostructured n-ZnO / thin film p-Si heterojunction is shown in Fig. 3(b) under a forward bias condition (Forward bias > the band gap of the ZnO). Several mid-gap oxygen-vacancy states and complexes are known to form in ZnO [24

A. Janotti and C. G. Van de Walle, “Oxygen vacancies in ZnO,” Appl. Phys. Lett. 87(12), 122102 (2005). [CrossRef]

]. As shown in Fig. 3 the CCD camera captured the emission of various colors related to these mid-gap states for the p-n device under forward bias.

Fig. 3 (a) I-V characteristics and (b) band diagram of the p-Si thin film / n-ZnO nanostructure heterojunction under forward bias. Increasing the forward bias allows holes in the valence band of Si to overcome the discontinuity of the valence band and recombine with the electrons in the conduction band of ZnO. Optical micrograph of the p-Si thin film / n-ZnO nanostructured heterojunction LED at (c) 0V and (d) 10V.

This experiment validated the ease in manipulating ZnO nanostructures via the DEP force to form a p-Si thin film / n-ZnO nanostructured heterojunction LED. This approach is generally applicable and has potential applications in nano-optoelectronics, for example, ZnO nanowires as light waveguides or ZnO nanostructures as light emitters with a silicon microelectronics chip.

4. Conclusion

We demonstrated that a p-Si thin film / n-ZnO nanostructures heterojunction LED can be readily formed by a straightforward DEP method. Under forward bias, the heterojunction p-n devices emitted near band edge emission as well as emission from oxygen vacancy related defect sites within the band gap of the ZnO. The current-voltage behavior is characteristic of operation via a p-n heterojunction. The slight deviation from an ideal p-n diode is believed to originate from a residual native oxide or nanoscale roughness at the ZnO / Si interface.

Acknowledgments

The research at Korea University was supported by the Carbon Dioxide Reduction and Sequestration Center, one of the 21st Century Frontier R&D Program funded by the Ministry of Education, Science and Technology of Korea and Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (Grant No. 2011-0027240 and 2011-0004270). The work at NRL was partially supported by ONR.

References and links

1.

Y. Li, F. Qian, J. Xiang, and C. M. Lieber, “Nanowire electronic and optoelectronic devices,” Mater. Today 9(10), 18–27 (2006). [CrossRef]

2.

Y. Huang, X. Duan, and C. M. Lieber, “Nanowires for integrated multicolor nanophotonics,” Small 1(1), 142–147 (2005). [CrossRef] [PubMed]

3.

D. Lucot, F. Jabeen, J.-C. Harmand, G. Patriarche, R. Giraud, G. Faini, and D. Mailly, “Quasi one-dimensional transport in single GaAs/AlGaAs core-shell nanowires,” Appl. Phys. Lett. 98(14), 142114 (2011). [CrossRef]

4.

A. Motayed, A. V. Davydov, M. He, S. N. Mohammad, and J. Melngailis, “365 nm operation of n-nanowire/p-gallium nitride homojunction light emitting diodes,” Appl. Phys. Lett. 90(18), 183120 (2007). [CrossRef]

5.

Y. J. Hong, C.-H. Lee, A. Yoon, M. Kim, H.-K. Seong, H. J. Chung, C. Sone, Y. J. Park, and G.-C. Yi, “Visible-color-tunable light-emitting diodes,” Adv. Mater. (Deerfield Beach Fla.) 23(29), 3284–3288 (2011). [CrossRef] [PubMed]

6.

K. Tomioka and T. Fukui, “Tunnel field-effect transistor using InAs nanowire/Si heterojunction,” Appl. Phys. Lett. 98(8), 083114 (2011). [CrossRef]

7.

E. C. Nelson, N. L. Dias, K. P. Bassett, S. N. Dunham, V. Verma, M. Miyake, P. Wiltzius, J. A. Rogers, J. J. Coleman, X. Li, and P. V. Braun, “Epitaxial growth of three-dimensionally architectured optoelectronic devices,” Nat. Mater. 10(9), 676–681 (2011). [CrossRef] [PubMed]

8.

T. Kuykendall, P. Ulrich, S. Aloni, and P. Yang, “Complete composition tunability of InGaN nanowires using a combinatorial approach,” Nat. Mater. 6(12), 951–956 (2007). [CrossRef] [PubMed]

9.

F. Qian, S. Gradečak, Y. Li, C.-Y. Wen, and C. M. Lieber, “Core/multishell nanowire heterostructures as multicolor, high-efficiency light-emitting diodes,” Nano Lett. 5(11), 2287–2291 (2005). [CrossRef] [PubMed]

10.

B. Prével, J.-M. Benoit, L. Bardotti, P. Mélinon, A. Ouerghi, D. Lucot, E. Bourhis, and J. Gierak, “Nanostructuring graphene on SiC by focused ion beam: effect of the ion fluence,” Appl. Phys. Lett. 99(8), 083116 (2011). [CrossRef]

11.

D. Kim, Y.-K. Kim, S. C. Park, J. S. Ha, J. Huh, J. Na, and G.-T. Kim, “Photoconductance of aligned SnO2 nanowire field effect transistors,” Appl. Phys. Lett. 95(4), 043107 (2009). [CrossRef]

12.

X. Chen, G. Cao, A. Han, V. K. Punyamurtula, L. Liu, P. J. Culligan, T. Kim, and Y. Qiao, “Nanoscale fluid transport: size and rate effects,” Nano Lett. 8(9), 2988–2992 (2008). [CrossRef] [PubMed]

13.

J. Ahn, M. A. Mastro, J. Hite, C. R. Eddy Jr, and J. Kim, “Violet electroluminescence from p-GaN thin film/n-GaN nanowire homojunction,” Appl. Phys. Lett. 96(13), 132105 (2010). [CrossRef]

14.

J. Ahn, M. A. Mastro, J. Hite, C. R. Eddy Jr, and J. Kim, “Electroluminescence from ZnO nanoflowers/GaN thin film p-n heterojunction,” Appl. Phys. Lett. 97(8), 082111 (2010). [CrossRef]

15.

H. A. Pohl, Dielectrophoresis (Cambridge University Press, 1978).

16.

G. H. Markx, M. S. Talary, and R. Pethig, “Separation of viable and non-viable yeast using dielectrophoresis,” J. Biotechnol. 32(1), 29–37 (1994). [CrossRef] [PubMed]

17.

B. R. Burg and D. Poulikakos, “Large-scale integration of single-walled carbon nanotubes and graphene into sensors and devices using dielectrophoresis: a review,” J. Mater. Res. 26(13), 1561–1571 (2011). [CrossRef]

18.

T. H. Kim, S. Y. Lee, N. K. Cho, H. K. Seong, H. J. Choi, S. W. Jung, and S. K. Lee, “Dielectrophoretic alignment of gallium nitride nanowires (GaN NWs) for use in device applications,” Nanotechnology 17(14), 3394–3399 (2006). [CrossRef] [PubMed]

19.

J. Aranovich, A. Ortiz, and R. H. Bube, “Optical and electrical properties of ZnO films prepared by spray pyrolysis for solar cell applications,” J. Vac. Sci. Technol. 16(4), 994 (1979). [CrossRef]

20.

X. W. Sun, J. Z. Huang, J. X. Wang, and Z. Xu, “A ZnO nanorod inorganic/organic heterostructure light-emitting diode emitting at 342 nm,” Nano Lett. 8(4), 1219–1223 (2008). [CrossRef] [PubMed]

21.

K. Kim, J. Kang, M. Lee, C. Yoon, K. Cho, and S. Kim, “Ultraviolet electroluminescence emission from n-type ZnO/p-type Si crossed nanowire light-emitting diodes,” Jpn. J. Appl. Phys. 49(6), 06GG05 (2010). [CrossRef]

22.

S. M. Sze, Physics of Semiconductor Devices (Wiley, 2007).

23.

J. A. Aranovich, D. Golmayo, A. L. Fahrenbruch, and R. H. Bube, “Photovoltaic properties of ZnO/CdTe heterojunctions prepared by spray pyrolysis,” J. Appl. Phys. 51(8), 4260–4268 (1980). [CrossRef]

24.

A. Janotti and C. G. Van de Walle, “Oxygen vacancies in ZnO,” Appl. Phys. Lett. 87(12), 122102 (2005). [CrossRef]

OCIS Codes
(230.0230) Optical devices : Optical devices
(230.3670) Optical devices : Light-emitting diodes
(230.4000) Optical devices : Microstructure fabrication

ToC Category:
Optical Devices

History
Original Manuscript: October 12, 2011
Manuscript Accepted: November 14, 2011
Published: December 6, 2011

Citation
Jaehui Ahn, Hyunik Park, Michael A. Mastro, Jennifer K. Hite, Charles R. Eddy, and Jihyun Kim, "Nanostructured n-ZnO / thin film p-silicon heterojunction light-emitting diodes," Opt. Express 19, 26006-26010 (2011)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-19-27-26006


Sort:  Author  |  Year  |  Journal  |  Reset  

References

  1. Y. Li, F. Qian, J. Xiang, and C. M. Lieber, “Nanowire electronic and optoelectronic devices,” Mater. Today9(10), 18–27 (2006). [CrossRef]
  2. Y. Huang, X. Duan, and C. M. Lieber, “Nanowires for integrated multicolor nanophotonics,” Small1(1), 142–147 (2005). [CrossRef] [PubMed]
  3. D. Lucot, F. Jabeen, J.-C. Harmand, G. Patriarche, R. Giraud, G. Faini, and D. Mailly, “Quasi one-dimensional transport in single GaAs/AlGaAs core-shell nanowires,” Appl. Phys. Lett.98(14), 142114 (2011). [CrossRef]
  4. A. Motayed, A. V. Davydov, M. He, S. N. Mohammad, and J. Melngailis, “365 nm operation of n-nanowire/p-gallium nitride homojunction light emitting diodes,” Appl. Phys. Lett.90(18), 183120 (2007). [CrossRef]
  5. Y. J. Hong, C.-H. Lee, A. Yoon, M. Kim, H.-K. Seong, H. J. Chung, C. Sone, Y. J. Park, and G.-C. Yi, “Visible-color-tunable light-emitting diodes,” Adv. Mater. (Deerfield Beach Fla.)23(29), 3284–3288 (2011). [CrossRef] [PubMed]
  6. K. Tomioka and T. Fukui, “Tunnel field-effect transistor using InAs nanowire/Si heterojunction,” Appl. Phys. Lett.98(8), 083114 (2011). [CrossRef]
  7. E. C. Nelson, N. L. Dias, K. P. Bassett, S. N. Dunham, V. Verma, M. Miyake, P. Wiltzius, J. A. Rogers, J. J. Coleman, X. Li, and P. V. Braun, “Epitaxial growth of three-dimensionally architectured optoelectronic devices,” Nat. Mater.10(9), 676–681 (2011). [CrossRef] [PubMed]
  8. T. Kuykendall, P. Ulrich, S. Aloni, and P. Yang, “Complete composition tunability of InGaN nanowires using a combinatorial approach,” Nat. Mater.6(12), 951–956 (2007). [CrossRef] [PubMed]
  9. F. Qian, S. Gradečak, Y. Li, C.-Y. Wen, and C. M. Lieber, “Core/multishell nanowire heterostructures as multicolor, high-efficiency light-emitting diodes,” Nano Lett.5(11), 2287–2291 (2005). [CrossRef] [PubMed]
  10. B. Prével, J.-M. Benoit, L. Bardotti, P. Mélinon, A. Ouerghi, D. Lucot, E. Bourhis, and J. Gierak, “Nanostructuring graphene on SiC by focused ion beam: effect of the ion fluence,” Appl. Phys. Lett.99(8), 083116 (2011). [CrossRef]
  11. D. Kim, Y.-K. Kim, S. C. Park, J. S. Ha, J. Huh, J. Na, and G.-T. Kim, “Photoconductance of aligned SnO2 nanowire field effect transistors,” Appl. Phys. Lett.95(4), 043107 (2009). [CrossRef]
  12. X. Chen, G. Cao, A. Han, V. K. Punyamurtula, L. Liu, P. J. Culligan, T. Kim, and Y. Qiao, “Nanoscale fluid transport: size and rate effects,” Nano Lett.8(9), 2988–2992 (2008). [CrossRef] [PubMed]
  13. J. Ahn, M. A. Mastro, J. Hite, C. R. Eddy, and J. Kim, “Violet electroluminescence from p-GaN thin film/n-GaN nanowire homojunction,” Appl. Phys. Lett.96(13), 132105 (2010). [CrossRef]
  14. J. Ahn, M. A. Mastro, J. Hite, C. R. Eddy, and J. Kim, “Electroluminescence from ZnO nanoflowers/GaN thin film p-n heterojunction,” Appl. Phys. Lett.97(8), 082111 (2010). [CrossRef]
  15. H. A. Pohl, Dielectrophoresis (Cambridge University Press, 1978).
  16. G. H. Markx, M. S. Talary, and R. Pethig, “Separation of viable and non-viable yeast using dielectrophoresis,” J. Biotechnol.32(1), 29–37 (1994). [CrossRef] [PubMed]
  17. B. R. Burg and D. Poulikakos, “Large-scale integration of single-walled carbon nanotubes and graphene into sensors and devices using dielectrophoresis: a review,” J. Mater. Res.26(13), 1561–1571 (2011). [CrossRef]
  18. T. H. Kim, S. Y. Lee, N. K. Cho, H. K. Seong, H. J. Choi, S. W. Jung, and S. K. Lee, “Dielectrophoretic alignment of gallium nitride nanowires (GaN NWs) for use in device applications,” Nanotechnology17(14), 3394–3399 (2006). [CrossRef] [PubMed]
  19. J. Aranovich, A. Ortiz, and R. H. Bube, “Optical and electrical properties of ZnO films prepared by spray pyrolysis for solar cell applications,” J. Vac. Sci. Technol.16(4), 994 (1979). [CrossRef]
  20. X. W. Sun, J. Z. Huang, J. X. Wang, and Z. Xu, “A ZnO nanorod inorganic/organic heterostructure light-emitting diode emitting at 342 nm,” Nano Lett.8(4), 1219–1223 (2008). [CrossRef] [PubMed]
  21. K. Kim, J. Kang, M. Lee, C. Yoon, K. Cho, and S. Kim, “Ultraviolet electroluminescence emission from n-type ZnO/p-type Si crossed nanowire light-emitting diodes,” Jpn. J. Appl. Phys.49(6), 06GG05 (2010). [CrossRef]
  22. S. M. Sze, Physics of Semiconductor Devices (Wiley, 2007).
  23. J. A. Aranovich, D. Golmayo, A. L. Fahrenbruch, and R. H. Bube, “Photovoltaic properties of ZnO/CdTe heterojunctions prepared by spray pyrolysis,” J. Appl. Phys.51(8), 4260–4268 (1980). [CrossRef]
  24. A. Janotti and C. G. Van de Walle, “Oxygen vacancies in ZnO,” Appl. Phys. Lett.87(12), 122102 (2005). [CrossRef]

Cited By

 Alert me when this paper is cited

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.

Figures

Fig. 1 Fig. 2 Fig. 3
 

« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited