奈米電子、光子晶體、磁性元件的研發有高度的吸引力，可能成為下一世代元件架構。 其中氧化鋅半導體具有無毒、低價、直遷寬能隙、極化等特性，在光電元件的應用上被視為有潛力的材料。本論文探討將一個維度的氧化鋅奈米結構運用至光電元件的研製，如光偵測器與場效電晶體等。主要研究分為以下四個部分討論。
首先，我們探討以氧化鋅奈米柱蕭特基能障之紫外光偵測器與光導偵測器之特性。使用水熱法與微影技術將奈米柱選區成長於指差狀電極的間隙，直立的奈米柱透過增加光子路徑和光電流效率能提供有效的光吸收的捕捉。其中金屬銀與氧化鋅之間的蕭特基能障為0.648 eV。元件在370 nm與5V偏壓下顯示出高的紫外光響應(41.22A/W)和在相對較低的光激發強度情況下，可產生出大約3個級數的增益，在雜訊等效功率和檢測度分別可達到4.81x10^-12 W 和3.22x10^10 cm Hz^0.5/W。
另外，在氧化鋅奈米柱與傳統薄膜光導偵測器的光響應顯示不同載子的動力。紫外光照射產生大量的光導增益，高密度的氧化鋅奈米柱有效增加載子的收集。與傳統氧化鋅薄膜元件相比，奈米柱元件呈現較慢的載子鬆弛動力，可歸因於氧化鋅奈米柱的高比表面積特性。而氧化鋅中高密度的表面電洞缺陷因而導致持續光導效應，促進載子傳送至元件。
其次，我們成長自組式且具方向性的氧化鋅奈米橋梁(橫式奈米柱)網路結構，並應用至光偵測器的製作。元件的組裝方法結合了傳統微影術與側向成核層達到在位的選區成長橫式且具方向性的氧化鋅奈米柱網路結構。當紫外光照射強度從1.79增加至57.46 mW/cm^2時，光電流相對暗電流的比增加至2~3個級數(在5V偏壓情況下)。光導增益計算的結果約為6.08x10^2，相當於光響應值為166.84 A/W。當給定偏壓5 V、頻率100 Hz時，其元件雜訊等效功率和檢測度分別為2.46x10^-11 W 和 1.23x10^9cm Hz^0.5/W。
我們也以上述的橫式氧化鋅奈米柱網路結構研製透明的光偵測器。在整個網路結構元件中，可見光區域的平均透光度大約70 %。當偏壓為5 V且在340 nm的照光條件下，透明光偵測器的光響應和紫外光/可見光的互斥比為175.58 A/W與207.63。在5 V與100 Hz情況下，元件的雜訊等效功率和檢測度分別為2.32x10^-10 W 和 4.36x10^8 cm Hz^0.5/W。這些結果顯示了此元件具再現性之光電流響應、高的光敏性、內部增益以及檢測度並在紫外光偵測具有潛在的應用。
第三，我們以水熱法製作垂直氧化鋅奈米柱之下閘極式電晶體。為了增強奈米柱電晶體電特性，奈米柱陣列選區成長於通道層中的源極與汲極之間。奈米柱電晶體的閘極偏壓(Vth)約18 V與傳統氧化鋅薄膜電晶體(Vth ~19 V)相比有相似的數據，在奈米柱電晶體中開關比和移動率(3.98x10^5，0.66 cm^2 V^−1s^−1)高於氧化鋅薄膜電晶體(2.2x10^4，0.29 cm^2V^−1s^−1)。在空乏狀態(VDS=-19 V, VGS=50 V)，奈米柱電晶體(γNR=4.6X10^5，R=0.2 A/W)中的相對光電導率(γ)和光響應(R)優於傳統薄膜電晶體(γfilm=2.27x10^2，R=1.06x10^-3 A/W)。垂直的氧化鋅奈米柱電晶體可經由改變汲極與閘極而調整通道導電率，在光偵測的應用上，可改善平面式偵測器的靈敏度並顯現出低功率損耗與高光靈敏度。
最後，以下而上(bottom-up)微影術組裝自組式具方向性的氧化鋅奈米柱網路結構之場效電晶體。當給定閘極偏壓時，輸出特性曲線顯示出良好的夾止特性且具較高的導電率。此元件的開關比超過10^4，移動率和臨限電壓約1.31 cm^2 V^-1 s^-1和 -1 V。當紫外光照射(340 nm, 57.46 mW/cm^2)，在空乏狀態(閘極偏壓-8V)，元件的相對光電導率和光響應增加至約2.08x10^5和1.56x10^3 A/W。
另外，我們也以自組式具方向性的氧化鋅奈米柱網路結構製作透明的場效電晶體並使用high-k二氧化鉿當作閘極介電層。整個元件在可見光區域(400~700nm)透光度大約為64.58%。此元件顯現出優異的電晶體特性，其開關比超過10^5，移動率和臨限電壓約7.59 cm^2 V^-1 s^-1和4 V。當以3.65 eV紫外光照射且在低偏壓的情況下(VGS=0 V, VDS=1 V)，元件的最高相對光電導率可達到約2.08x10^5，相當於3.96 A/W的光響應。其結果顯示當奈米柱的元件運用至光偵測時有低的功率損耗與較高的光響應。

Developing integrated nanoelectronic, nanophotonic and nanomagnetic devices draw highly attractive potential as next-generation device architecture. ZnO-based semiconductors have been regarded as one of the strongest candidates for optoelectronic devices considering their non-toxic, low price, a direct wide band gap, electronic, optical, and piezoelectric properties. This dissertation describes the fabrication and characterization of optoelectronic devices (photodetectors (PDs) and field-effect transistors (FETs)) with one-dimensional ZnO nanostructures. The main investigation can be divided into the following four parts.
First, we elucidate the characteristics of Schottky barrier UV PDs and photoconductive detectors with ZnO nanorods (NRs). The NRs are selectively distributed among the electrodes using hydrothermal solution processes and a lithography-based technique, which can enables precise positioning and inexpensively to fabricate devices. The free-standing NR provides efficient light trapping absorption by increasing the photon path length and the photocurrent efficiency. It was found that the barrier height at the silver/ZnO interface was 0.648 eV. The devices exhibit a high UV photocurrent efficiencies with a responsivity of 41.22 A/W (370 nm, 5 V), and the gain is approximately three orders of magnitude as the UV illumination intensity is varied at relatively low excitation intensity. The noise equivalent power and the corresponding detectivity of the NRs-based UV devices were 4.81x10^-12 W and 3.22x10^10 cm Hz^0.5/W, respectively.
Additionally, the photoresponses of ZnO NR photoconductive detectors exhibit very different photocarrier dynamics from those of conventional ZnO film photoconductive detectors. UV-treatment causes a large photoconductive gain and the high density of ZnO NR arrays increases the charge collection efficiency. ZnO NR devices have slower carrier relaxation dynamics than conventional ZnO film devices, which can be attributed to high surface-to-volume ratio of ZnO NRs. The high density of hole-trap states on NR surfaces lead to a persistent photoconductivity state, promoting the transport of carriers through devices.
Second, we demonstrate the self-assembly of ordered ZnO nanobridge (i.e. ZnO NRs) networks for use in photodetection applications. The fabrication approach, which combines conventional photolithography with sidewall nucleation sites, achieves site specificity and the self-assembly of an ordered ZnO NR networks. The current generated as the UV illumination intensity was increased from 1.79 to 57.46mW/cm^2 increased from two to three orders of magnitude higher than the dark current (at an applied bias of 5V). The photoconductive gain is estimated to be 6.08x10^2, corresponding to a photoresponsivity of 166.84 A/W at an applied bias of 5 V. With a 5V applied bias and a bandwidth of 100 Hz, the noise equivalent power and corresponding detectivity D* of the devices were 2.46x 10^-11 W and 1.23x10^9 cm Hz^0.5/W, respectively.
We also describe the fabrication of transparent UV PDs with self-assembling ordered ZnO NR networks. The average optical transmission of the entire network devices structure in the visible range of the spectrum is about 70%. At an applied bias of 5 V and 340nm irradiation, the photoresponsivity and the ratio of UV to visible rejection was 175.58 A/W and 207.63 for the transparent PDs. For a bandwidth of 100 Hz and an applied bias of 5 V, the noise equivalent power and normalized detectivity of the devices were 2.32x10^-10 W and 4.36x10^8 cm Hz^0.5/W, respectively. These results reveal that the reproducible photocurrent response, high-photosensivity, internal gain and detectivity suggest that the device has potential applications in UV photodetection.
Third, we show the bottom-contact-type transistors with free-standing ZnO NR arrays that were fabricated by hydrothermal decomposition. The NR arrays were selectively grown in channel layer between the source and drain electrodes in order to enhance the electrical characteristics of the NR transistors. The threshold voltage (Vth) of the ZnO NR transistors is approximately ~18 V, which is similar to the value for conventional ZnO film transistors (Vth ~19 V). The on/off current ratio and mobility of ZnO NR transistors (3.98x10^5, 0.66 cm^2 V^−1 s^−1) is higher than that of the ZnO film transistors (2.2x10^4, 0.29 cm^2 V^−1 s^−1). The relative photoconductivity (γ) and photoresponsivity (R) of NR transistors (γNR=4.6X10^5, R=0.2 A/W) perform better than conventional film transistors (γfilm=2.27x10^2, R=1.06x10^-3 A/W) in the depletion region (VDS=-19V, VGS=50V). However, the channel conductance of free-standing NR transistors can be manipulated by changing the drain and gate voltages for use in photodetection applications, which could be applied to improve sensitivity of planar detector, exhibiting low power consumption and high photosensivity.
Finally, self-assembling ordered ZnO NR network-based FETs were fabricated by bottom-up photolithography. The output curves exhibited pinch-off behavior and good modulation of the channel conductance by the applied gate voltage. The devices had ON/OFF ratios of > 10^4, mobilities of ~1.31 cm^2 V^-1 s^-1, and threshold voltages of ~ -1 V. Under UV treatment (340nm, 57.46 mW/cm^2), the devices exhibited relative photoconductivity ratio increases of 10^5 at a depletion state of -8V gate bias (1.56x10^3 A/W).
Additionally, we also describe the fabrication of semi-transparent FETs with self-assembling ordered ZnO NR networks, using a high-k HfO2 gate. The average optical transmission of the entire devices in the visible range (400~700nm) of the spectrum is around 64.58%. The devices exhibit excellent transistor performance at ON/OFF ratios of > 10^5, a mobility of ~7.59 cm^2 V^-1 s^-1, and threshold voltages of ~ 4 V. Under UV illumination (3.65 eV), the devices exhibit the highest relative photoconductivity (~2.08x10^5), corresponding to a photoresponsivity of 3.96 A/W at low operating voltage (VGS=0V, VDS=1V). These results suggest that the NR-based devices have the low power consumption and high photosensivity when used in photodetection.

[1] P. Yang, R. Yan, and M. Fardy, “Semiconductor Nanowire: What’s Next?,” Nano Lett., vol. 10, pp. 1529–1536, 2010.
[2] R. S. Wagner and W. C. Ellis, Vapor-liquid-solid mechanism of single crystal growth,” Appl Phys Lett., vol. 4, no. 5, pp. 89–90, 1964.
[3] E. I. Givargizov, “Fundamental aspects of VLS growth,” J. Cryst. Growth, vol. 31, pp. 20–30, 1975.
[4] L. Schubert, P. Werner, N. D. Zakharov, G. Gerth, F. M. Kolb, L. Long, U. Gosele, and T. Y. Tan, Silicon nanowhiskers grown on <111> Si substrates by molecula-beam epitaxy,” Appl. Phys. Lett., vol. 84, pp. 4968–4970, 2004.
[5] J. L. Liu, S. J. Cai, G. L. Jin, S. G. Thomas, and K. L. Wang, “Growth of Si whiskers on Au/Si (111) substrate by gas source molecular beam epitaxy (MBE),” J. Cryst. Growth, vol. 200, pp. 106–111, 1999.
[6] S. Q. Feng, D. P. Yu, H. Z. Zhang, Z. G. Bai, and Y. Ding, J. Cryst. Growth, “The growth mechanism of silicon nanowires and their quantum confnement effect,” vol. 209, pp. 513–517, 2000.
[7] V. Sivakov, F. Heyroth, F. Falk, G. Andra, and S. Christiansen, “Silicon nanowire growth by electron beam evaporation: Kinetic and energetic contributions to the growth morphology,” J. Cryst. Growth, vol. 300, pp. 288–93, 2007.
[8] N. R. B. Coleman, M. A. Morris, T. R. Spalding, and J. D. Holmes, “The Formation of Dimensionally Ordered Silicon Nanowires within Mesoporous Silica,” J. Am. Chem. Soc., vol. 123, pp. 187–8, 2001.
[9] J. Mallet, M. Molinari, F. Martineau, F. Delavoie, P. Fricoteaux, and M. Troyon, “Growth of Silicon Nanowires of Controlled Diameters by Electrodeposition in Ionic Liquid at Room Temperature,” Nano Lett. vol. 8, no. 10, pp. 3468–3474, 2008.
[10] A. I. Persson, M. W. Larsson, S. Stenstrom, B. J. Ohlsson, L. Samuelson, and L. R. Wallenberg, “Solid-phase diffusion mechanism for GaAs nanowire growth,” Nat. Mater. vol. 3, pp. 677–81, 2004.
[11] I. Regolin, V. Khorenko, W. Prost, F. J. Tegude, D. Sudfeld, J. Kastner, G. Dumpich, K. Hitzbleck, and H. Wiggers, “GaAs whiskers grown by metal-organic vapor-phase epitaxy using Fe nanoparticles,” J. Appl. Phys. vol. 101, pp. 054318, 2007.
[12] H. Morkoc, R. Stamberg and E. Krikorian, "Whisker Growth during Epitaxy of GaAs by Molecular Beam Epitaxy", J. J. Appl. Phys., vol. 21, no. 4, pp. L230-L232, 1982.
[13] C. Colombo, D. Spirkoska, M. Frimmer, G. Abstreiter, A. F. I. Morral, “Ga-assisted catalyst-free growth mechanism of GaAs nanowires by molecular beam epitaxy,” Phys. Rev. B, vol. 77, pp. 155326, 2008.
[14] Y. G. Sun, V. Kumar, I. Adesida, and J. A. Rogers, “Buckled and Wavy Ribbons of GaAs for High-Performance Electronics on Elastomeric Substrates,” Adv. Mater., vol. 18, pp. 2857–2862, 2006.
[15] Y. Sun and J. A. Rogers, “Fabricating semiconductor nano/microwires and transfer printing ordered arrays of them onto plastic substrates,” Nano Lett. vol. 4, no. 10, pp. 1953–1959, 2004.
[16] P. Zhu, H. Kang, A. Facchetti, G. Evmenenko, P. Dutta, and T. J. Marks, J. Am. Chem. Soc., vol. 125, pp. 11496–11497, 2003.
[17] Y. J. Hsu and S. Y. Lu, “Low temperature growth and dimension- dependent photoluminescence efficiency of semiconductor nanowires,” Appl. Phys. A, vol. 81, no. 3, pp. 573–578, 2005.
[18] Y. Wang, G. Meng, L. C. Zhang, C. Liang and J. Zhang, “Catalytic Growth of Large-Scale Single-Crystal CdS Nanowires by Physical Evaporation and Their Photoluminescence,” Chem. Mater., vol. 14, no. 4, pp. 1773–1777, 2002.
[19] S. Kar, B. Satpati, P. V. Satyam and S. Chaudhuri, “Synthesis and Optical Properties of CdS Nanoribbons,” J. Phys. Chem. B, vol. 109, no. 41, pp. 19134–19138, 2005.
[20] D. Routkevich, T. Bigioni, M. Moskovits and J. M. Xu, "Electrochemical Fabrication of CdS Nanowire Arrays in Porous Anodic Aluminum Oxide Templates," J. Phys. Chem., vol. 100, pp. 14037–14047, 1996.
[21] D. Xu, Y. Xu, D. Chen, G. Guo, L. Gui and Y. Tang, “Preparation of CdS Single-Crystal Nanowires by Electrochemically Induced Deposition,” Adv. Mater., vol. 12, no. 7, pp. 520–522, 2000.
[22] W. I. Park, D. H. Kim, S. W. Jung, G. C. Yi, “Metalorganic vapor-phase epitaxial growth of vertically well-aligned ZnO nanorods,” Appl. Phys. Lett., vol. 80, no. 22, pp. 4232–4234, 2002.
[23] W. I. Park and G. C. Yi. “Electroluminescence in n-ZnO Nanorod Arrays Vertically Grown on p-GaN,”Adv. Mater., vol. 16, no. 1, pp. 87–90, 2004.
[24] Y. W. Heo, V. Varadarajan, M. Kaufman, K. Kim, D. P. Norton, F. Ren and P. H. Fleming, “Site-specific growth of Zno nanorods using catalysis-driven molecular-beam epitaxy,” Appl. Phys. Lett. vol. 81, no. 16, pp. 3046–3048, 2002.
[25] Z. R. Dai, Z. W. Pan and Z. L. Wang, “Novel nanostructures of functional oxides synthesized by thermal evaporation,” Adv. Funct. Mater., vol. 13, pp. 9–24, 2003.
[26] Z. L. Wang, X. Y. Kong, J. M. Zou, “Induced Growth of Asymmetric Nanocantilever Arrays on Polar Surfaces,” Phys. Rev. Lett. vol. 91, pp. 185502, 2003.
[27] C. C. Chen, C. C. Yeh, C. H. Chen, M. Y. Yu, H. L. Liu, J. J. Wu, K. H. Chen, L. C. Chen,J. Y. Peng, and Y. F. Chen, “Catalytic Growth and Characterization of Gallium Nitride Nanowires,” J. Am. Chem. Soc., vol. 123, pp. 2791–2798, 2001.
[28] X. Chen, J. Xu, R. M. Wang and D. Yu, “High-Quality Ultra-Fine GaN Nanowires Synthesized Via Chemical Vapor Deposition,” Adv. Mater., vol. 15, no. 5, pp. 419–421, 2003.
[29] J. Zhang, L. D. Zhang, X. F. Wang, C. H. Liang, X. S Peng and Y. W. Wang, “Fabrication and photoluminescence of ordered GaN nanowire arrays,” J. Chem. Phys., vol. 115, no. 13, pp. 5714–5717, 2001.
[30] G. S. Cheng, L. D. Zhang, Y. Zhu, G. T. Fei, L. Li, C. M. Mo and Y. Q. Mao, “Large-scale synthesis of single crystalline gallium nitride nanowires,” Appl. Phys. Lett., vol. 75, no. 16, pp. 2455–2457, 1999.
[31] C. Youtsey, L. T. Romano and I. Adesia, Appl. Phys. Lett., “Gallium nitride whiskers formed by selective photoenhanced wet etching of dislocations,” vol. 73, no. 6, pp. 797–9, 1998.
[32] S. Mathur, S. Barth, H. Shen, J. C. Pyun and U. Werner, “Size-Dependent Photoconductance in SnO2 Nanowires,” Small, vol. 1, no. 7, pp. 713–717, 2005.
[33] S. Mathur and S. Barth, “Molecule-Based Chemical Vapor Growth of Aligned SnO2 Nanowires and Branched SnO2/V2O5 Heterostructures,” Small, vol. 3, no. 12, pp. 2070–2075, 2007.
[34] Z. R. Dai, Z. W. Pan and Z. L. Wang, “Ultra-long single crystalline nanoribbons of tin oxide,” Solid State Commun., vol. 118, no. 7, pp. 351–354, 2001.
[35] J. Zhang, F. Jiang and L. Zhang, “Fabrication, structural characterization and optical properties of semiconducting gallium oxide nanobelts,” Phys. Lett. A, vol. 322, no. 5–6, pp. 363–368, 2004.
[36] M. J. Zheng, G. H. Li, X. Y. Zhang, S. Y. Huang, Y. Lei and L. D. Zhang, “Fabrication and Structural Characterization of Large-Scale Uniform SnO2 Nanowire Array Embedded in Anodic Alumina Membrane,” Chem. Mater., vol. 13, no. 11, pp. 3859–3861, 2001.
[37] A. Kolmakov, Y. Zhang, G. Cheng and M. Moskovits, “Detection of CO and O2 Using Tin Oxide Nanowire Sensors,” Adv. Mater., vol. 15, no. 12, pp. 997–1000, 2003.
[38] Y. Wang, M. Aponte, N. Leon, I. Ramos, R. Furlan, N. Pinto, S. Evoy and J. J. Santiago-Aviles, “Synthesis and Characterization of Ultra-Fine Tin Oxide Fibers Using Electrospinning,” J. Am. Ceram. Soc., vol. 88, no. 8, pp. 2059–63, 2005.
[39] Y. Wang, M. Aponte, N. Leon, I. Ramos, R. Furlan, S. Evoy and J. J. Santiago-Aviles, “Synthesis and characterization of tin oxide microfibres electrospun from a simple precursor solution,” Semicond. Sci. Technol., vol. 19, no. 8, pp. 1057–1060, 2004.
[40] X. F. Duan, C. M. Niu, V. Sahi, J. Chen, J. W. Parce, S. Empedocles and J. L. Goldman, “High-performance thin-film transistors using semiconductor nanowires and nanoribbons,” Nature, vol. 425, pp. 274–278, 2003.
[41] S. Jin, D. M. Whang, M. C. McAlpine, R. S. Friedman, Y. Wu and C. M. Lieber, “Scalable Interconnection and Integration of Nanowire Devices without Registration,” Nano Lett., vol. 4, no. 5, pp. 915–919, 2004.
[42] G. Yu, A. Cao and C. M Lieber,. “Large-area blown bubble films of aligned nanowires and carbon nanotubes,” Nat. Nanotechnol., vol. 2, pp. 372–377, 2007.
[43] P. A. Smith, C. D. Nordquist, T. N. Jackson, T. S. Mayer, B. R. Martin, J. Mbindyo and T. E. Mallouk, “Electric-field assisted assembly and alignment of metallic nanowires,” Appl. Phys. Lett., vol. 77, no. 9, pp. 1399–1401, 2000.
[44] R. Yerushalmi, Z. A. Jacobson, J. C. Ho, Z. Fan and A. Javey, “Large scale, highly ordered assembly of nanowire parallel arrays by differential roll printing,” Appl. Phys. Lett., vol. 91, pp. 203104, 2007.
[45] G. Shen and D. Chen, “One-Dimensional Nanostructures for Photodetectors,” Recent Patents on Nanotechnology vol. 4, no. 1, 20–31, 2010.
[46] Z. L. Wang, “Piezotronic and Piezophototronic Effects,” |J. Phys. Chem. Lett., vol. 1, no. 9, pp. 1388–1393, 2010.
[47] U. Ozgur, Y. I. Alivov, C. Liu, A. Teke, M. A. Reshchikov, S. Dogan, V. Avrutin, S. J. Cho and H. Morkocd, “A comprehensive review of ZnO materials and devices,” J. Appl. Phys., vol. 98, pp. 041301, 2005.
[48] K. Vanheusden, C. H. Seager, W. L. Warren, D. R. Tallant and J. A. Voigt, “Correlation between photoluminescence and oxygen vacancies in ZnO phosphors,” Appl. Phys. Lett., vol. 68, no. 3, pp. 403–405, 1996.
[49] A. van Dijken, E. A. Meulenkamp, D. Vanmaekelbergh and A. Meijerink, “The Kinetics of the Radiative and Nonradiative Processes in Nanocrystalline ZnO Particles upon Photoexcitation,” J. Phys. Chem. B, vol. 104, no. 8, pp. 1715–1723, 2000.
[50] B. Lin, Z. Fu and Y. Jia, Appl. Phys. Lett., “Green luminescent center in undoped zinc oxide films deposited on silicon substrates,” vol. 79, no. 7, pp. 943–945, 2001.
[51] Q. X. Zhao, P. Klason, M. Willander, H. M. Zhong, W. Lu and J. H. Yang, “Deep-level emissions influenced by O and Zn implantations in ZnO,” Appl. Phys. Lett., vol. 87, pp. 211912, 2005.
[52] L. E. Greene, M. Law, J. Goldberger, F. Kim, J. C. Johnson, Y. Zhang, R. J. Saykally and P. Yang, “Low-Temperature Wafer-Scale Production of ZnO Nanowire Arrays,” Angew. Chem., Int. Ed., vol. 42, pp. 3031–3034, 2003.
[53] S. E. Ahn, J. S. Lee, H. Kim, S. Kim, B. H. Kang, K. H. Kim and G. T. Kim, “Photoresponse of sol-gel-synthesized ZnO nanorods,” Appl. Phys. Lett., vol. 84, no. 24, pp. 5022–5024, 2004.
[54] R. Xie, T. Sekiguchi, T. Ishigaki, N. Ohashi, D. Li, D. Yang, B. Liu and Y. Bando, “Enhancement and patterning of ultraviolet emission in ZnO with an electron beam,” Appl. Phys. Lett., vol. 88, pp. 134103, 2006.
[55] Bera, A.; Basak, D. “Role of defects in the anomalous photoconductivity in ZnO nanowires,” Appl. Phys. Lett. vol. 94, pp. 163119, 2009.
[56] Z. L. Wang “Piezoelectric nanostructures: from growth phenomena to electric nanogenerators”, Mrs Bulletin, vol. 32, pp. 109–116, 2007.
[57] S. Kim and J. Maier, “Electrical Properties of ZnO,” Electrochem. Solid-State Lett. vol. 6. no. 11, J7–J9, 2003.
[58] C. Soci, A. Zhang, B. Xiang, S. A. Dayeh, D. P. R. Aplin, J. Park, X. Y. Bao, Y. H. Lo and D. Wang, “ZnO Nanowire UV Photodetectors with High Internal Gain,” Nano Lett. vol. 7, no. 4, pp. 1003–1009, 2007.
[59] M. Razeghi and A. Rogalski, “Semiconductor ultraviolet detectors, ” J. Appl. Phys. vol. 79, no. 10, 7433–7473, 1996.
[60] S. M. Sze, “Physics of Semiconductor Devices, 2nd ed.,” Wiley: New York, 1981.
[61] D. Walker, M. Razeghi, “The development of nitride-based UV photodetector,” Opto-electronics review, vol. 8, pp. 25–42, 2000.
[62] Y. Jin, J. Wang, B. Sun, J. C. Blakesley, and N. C. Greenham, “Solution-processed ultraviolet photodetectors based on colloidal ZnO nanoparticles,” Nano Lett., vol. 8, no. 6, pp. 1649–1653, 2008.
[63] Y. K. Seo, S. Kumar and G. H. Kim, “Photoconductivity characteristics of ZnO nanoparticles assembled in nanogap electrodes for portable photodetector applications,” Physica E, vol. 42, pp. 1163–1166, 2010.
[64] G. Chai, O. Lupan, L. Chow and H. Heinrich, “Crossed zinc oxide nanorods for ultraviolet radiation detection,” Sensors and Actuators A, vol. 150, pp. 184–187, 2009.
[65] T. J. Hsueh, C. L. Hsu, S. J. Chang, Y. R. Lin, S. P. Chang, Y. Z. Chiou, T. S. Lin and I. C. Chen, “Crabwise ZnO nanowire UV photodetector prepared on ZnO : Ga/Glass template”, IEEE Transactions on Nanotechnology,” IEEE T. Nanotech., vol. 6, no. 6, pp. 595–600, 2007.
[66] S. S. Hullavarad, N. V. Hullavarad, P. C. Karulkar, A. Luykx and P. Valdivia, “Ultra violet sensors based on nanostructured ZnO spheres in network of nanowires: a novel approach,” Nanoscale Res. Lett., vol. 2, no. 3, pp. 161–167, 2007.
[67] Y. Li, F. D. Valle, M. Simonnet, I. Yamada and J. J. Delaunay, “High performance UV detector made of ultra-ling ZnO bridging nanowires,” Nanotechnology, vol. 20, pp. 045501, 2009.
[68] H. Kind, H. Yan, B. Messer, M. Law and P. Yang, “Nanowire Ultraviolet photodetectors and optical switches,” Adv. Mater., vol. 14, no. 2, pp. 158-160, 2002.
[69] O. Lupan, L. Chow, G. Chai, L. Chernyak, O. Lopatiuk-Tirpak and H. Heinrich, “Focused-ion-beam fabrication of ZnO nanorod-based UV photodetector using the in-situ lift-out technique,” Phys. Stat. Sol. A, vol. 205, no. 11, pp. 2673-2678, 2008.
[70] J. P. Kar, S. N. Das, J. H. Choi, Y. A. Lee, T. Y. Lee and J. M. Myoung, “Fabrication of UV detectors based on ZnO nanowires using silicon microchannel,” J. Cryst. Growth., vol. 311, pp. 3305-3309, 2009.
[71] K. J. Chen, F. Y. Hung, S. J. Chang and S. J. Young, “Optoelectronic characteristics of UV photodetector based on ZnO nanowire thin films,” J. Alloy Compd., vol. 479, pp. 674-677, 2009.
[72] D. Lin, H. Wu, W. Zhang, H. Li and W. Pan, “Enhanced UV photoresponse from heterostructured Ag-ZnO nanowires,” Appl. Phys. Lett., vol. 94, pp. 172103, 2009.
[73] P. Feng, J. Y. Zhang, Q. Wan, T. H. Wang, “Photocurrent characteristics of individual ZnGa2O4 nanowires,” J. Appl. Phys., vol. 102, pp. 074309, 2007.
[74] X. Y. Xue, T. L. Guo, Z. X. Lin and T. H. Wang, “Individual core-shell structured ZnSnO3 nanowires as photoconductors,” Mater. Lett., vol. 62, pp. 1356-1358, 2008.
[75] S. Ju, A. Facchetti, Y. Xuan, J. Liu, F. Ishikawa, P. Ye, C. Zhou, T. J. Marks, and D. B. Janes, “Fabrication of fully transparent nanowire transistors for transparent and flexible electronics,” Nature Nanotech., vol. 2, pp. 378–384, 2007.
[76] P. C. Chang, Z. Fan, C. J. Chien, D. Stichtenoth, C. Ronning, and J. G. Lu, “High-performance ZnO nanowire field effect transistors,” Appl. Phys. Lett., vol. 89, no. 13, p. 133113, 2006.
[77] S. Ju, D. B. Janes, G. Lu, A. Facchetti, and T. J. Marks, “Effects of bias stress on ZnO nanowire field-effect transistors fabricated with organic gate nanodielectrics,” Appl. Phys. Lett., vol. 89, no. 19, pp. 193506, 2006.
[78] S. Ju, K. Lee, D. B. Janes, R. C. Dwivedi, H. Baffour-Awuah, R. Wilkins, M.-H. Yoon, A. Facchetti, and T. J. Mark, “Proton radiation hardness of single-nanowire transistors using robust organic gate nanodielectrics,” Appl. Phys. Lett., vol. 89, no. 7, pp. 073510, 2006.
[79] H. T. Ng, J. Han, T. Yamada, P. Nguyen, Y. P. Chen, and M. Meyyappan, “Single crystal nanowire vertical surround-gate field-effect transistor,” Nano Lett., vol. 4, no. 7, pp. 1247–1252, 2004.
[80] Y. W. Heo, L. C. Tien, Y. Kwon, D. P. Norton, S. J. Pearton, B. S. Kang, and F. Ren, “Depletion-mode ZnO nanowire field-effect transistor,” Appl. Phys. Lett., vol. 85, no. 12, pp. 2274–2276, 2004.
[81] S. H. Ko, I. Park, H. Pan, N. Misra, M. S. Rogers, C. P. Grigoropoulos, A. P. Pisano, “ZnO nanowire network transistor fabrication on a polymer substrate by low-temperature, all-inorganic nanoparticle solution process,” Appl. Phys. Lett., vol. 92, pp. 154102, 2008.
[82] B. Sun, R. L. Peterson, H. Sirringhaus, K. Mori, “Low-Temperature Sintering of In-Plane Self-Assembled ZnO Nanorods for Solution-Processed High-Performance Thin Film Transistos,” J. Phys. Chem. C, vol. 111, no. 51, pp. 18831–18835, 2007.
[83] H. E. Unalan, Y. Zhang, P. Hiralal, S. Dalal, D. Chu, G. Eda, K. B. K. Teo, M. Chhowalla, W. I. Milne, G. A. J. Amaratung, “Zinc oxide nanowire networks for macroelectronic devices,” Appl. Phys. Lett., vol. 94, pp. 163501, 2009.
[84] Y. K. Chang, F. C. N. Hong, “The fabrication of ZnO nanowire field-effect transistors by roll-transfer printing,” Nanotechnology, vol. 20, pp. 195302, 2009.
[85] Y. Zhang, H. B. Jia, R. M. Wang, C. P. Chen, X. H. Luo, D. P. Yu and C. J. Lee, “Low-temperature growth and Raman scattering study of vertically aligned ZnO nanowires on Si substrate,” Appl. Phys. Lett., vol. 83, no. 22, pp. 4631–4633, 2003.
[86] Y. J. Lee, D. S. Ruby, D. W. Peters, B. B. McKenzie, and J. W. P. Hsu, “ZnO nanostructures as efficient antireflection layers in solar cells,” Nano Lett., vol. 8, no. 5, pp. 1501–1505, 2008.
[87] Z. M. Liao, Y. Lu, J. Xu, J. M. Zhang, and D. P. Yu, “Temperature dependence of photoconductivity and persistent photoconductivity of single ZnO nanowires,” Appl. Phys. A, vol. 95, no. 2, pp. 363–366, 2009.
[88] D. Jiang, J. Zhang, Y. Lu, K. Liu, D. Zhao, Z. Zhang, D. Shen and X. Fan, “Ultraviolet Schottky detector based on epitaxial ZnO thin film,”Solide-State Electronics, vol. 52, 679–682, 2008.
[89] Q. H. Li, T. Gao, Y. G. Wang and T. H. Wang, “Adsorption and desorption of oxygen probed from ZnO nanowire films by photocurrent measurements,”Appl. Phys. Lett., vol. 86, pp. 123117, 2005.
[90] S. W. Lee, M. C. Jeong, J. M. Myoung, G. S. Chae and I. J. Chung, “Magnetic alignment of ZnO nanowires for optoelectronic device applications,” Appl. Phys. Lett. vol. 90, pp. 133115, 2007.
[91] J. D. Prades, F. H. Ramirez, R. J. Diaz, M. Manzanares, T. Andreu, A. Cirera, A. R. Rodriguez and J. R. Morante, “The effects of electron–hole separation on the photoconductivity of individual metal oxide nanowires,” Nanotechnology, vol. 19, no. 46, pp. 465501, 2008.
[92] F. N. Hooge, J. Kedzia, and L. K. J. Vandamme, “Boundary scattering and 1/f noise,” J. Appl. Phys., vol. 50, no. 12, pp. 8087–8089, 1979.
[93] S. Papatzika, N. A. Hastas, C. T. Angelis, C. A. Dimitriadis, G. Kamarinos, and J. I. Lee, “Investigation of noise sources in platinum silicide Schottky barrier diodes,” Appl. Phys. Lett., vol. 80, no. 8, pp. 1468–1470, 2002.
[94] C. Y. Lu, S. P. Chang, S. J. Chang, Y. Z. Chiou, C. F. Kuo, H. M. Chang, C. L. Hsu, and I. C. Chen, "Noise characteristics of ZnO-nanowire photodetectors prepared on ZnO:Ga/glass templates", IEEE Sensors J., vol. 7, pp. 1020–1024, 2007.
[95] W. Y. Weng, S. J. Chang, C. L. Hsu, T. J. Hsueh, and S. P. Chang, “A Lateral ZnO Nanowire Photodetector Prepared on Glass Substrate,” J. Electrochem. Soc., vol. 157, no. 2, K30–K33, 2010.
[96] P. X. Gao, J. Liu, B. A. Buchine, B. Weintraub, Z. L. Wang and J. L. Lee, “Bridged ZnO nanowires across trenched electrodes,” Appl. Phys. Lett., vol. 91, pp. 142108, 2007.
[97] J. S. Lee, M. S. Islam and S. Kim, “Direct Formation of Catalyst-Free ZnO Nanobridge Devices on an Etched Si Substrate Using a Thermal Evaporation Method,” Nano Lett., vol. 6, no.7, pp. 1487–1490, 2006.
[98] L. W. Ji, S. M. Peng, Y. K. Su, S. J. Young, C. Z. Wu and W. B. Cheng, “Ultraviolet photodetectors based on selectively grown ZnO nanorod arrays,” Appl. Phys. Lett., vol. 94, pp. 203106, 2009.
[99] H. W. Seo, S. Y. Bae, J. Park, H. Yang, K. S. Park and S. Kim, “Strained gallium nitride nanowires,” J. Chem. Phys. vol. 116, no. 21, pp. 9492–9499, 2002.
[100] F. Decremps, J. Pellicer-Porres, A. M. Saitta, J. C. Chervin and A. Polian, “High-pressure Raman spectroscopy study of wurtzite ZnO,” Phys. Rev. B, vol. 65, pp.092101, 2002.
[101] S. J. Chen, Y. C. Liu, C. L. Shao, C. S. Xu, Y. X. Liu, L. Wang, B. B. Liu and G. T. Zou, “Pressure-dependent photoluminescence of ZnO nanosheets,” J. Appl. Phys., vol. 98, pp. 106106, 2005 .
[102] S. E. Ahn, H. J. Ji, K. Kim, G. T. Kim, C. H. Bae, S. M. Park, Y. K. Kim and J. S. Ha, “Origin of the slow photoresponse in an individual sol-gel synthesized ZnO nanowire,” Appl. Phys. Lett., vol. 90, pp. 153106, 2007.
[103] Liao Z. M.; Hou C.; Zhou Y. B.; Xu J.; Zhang J. M.; Yu D. P. “Influence of temperature and illumination on surface barrier of individual ZnO nanowires,” J. Chem. Phys., vol. 130, pp. 084708. 2009.
[104] J. Zhou, P. Fei, Y. Gu, W. Mai, Y. Gao, R. Yang, G. Bao, Z. L. Wang, “Piezoelectric-Potential-Controlled Polarity-Reversible Schottky Diodes and Switches of ZnO Wires,” Nano Lett., vol. 8, no. 11, pp. 3973–3977, 2008.
[105] Z. L. Wang, “Towards Self-Powered Nanosystems: From Nanogenerators to Nanopiezotronics,”Adv. Funct. Mater., vol. 18, no. 22, pp. 3553–3557, 2008.
[106] J. Zhou, P. Fei, Y. Gu, W. Mai, Y. Gao, R. Yang, G. Bao, Z. L. Wang, “Piezoelectric-Potential-Controlled Polarity-Reversible Schottky Diodes and Switches of ZnO Wires,” Nano Lett., vol. 8, no. 11, pp. 3973–3977, 2008.
[107] J. H. He, C. L. Hsin, J. Liu, L. J. Chen and Z. L. Wang, “Piezoelectric Gated Diode of a Single ZnO Nanowire,” Adv. Mater., vol. 19, no. 6, pp. 781–784, 2007.
[108] J. D. Ye, S. L. Gu, F. Qin, S. M. Zhu, S. M. Liu, X. Zhou, W. Liu, L. Q. Hu, R. Zhang, Y. Shi, Y. D. Zheng, “Correlation between green luminescence and morphology evolution of ZnO films,” Appl. Phys. A, vol. 81, no. 4, pp. 759–762, 2005.
[109] P. Feng, Q. Wan and T. H. Wang, “Contact-controlled sensing properties of flowerlike ZnO nanostructures,” Appl. Phys. Lett., vol. 87, pp. 213111, 2005.
[110] K. W. Chung, Z. Wang, J. C. Costa, F. Willamson, “Barrier height change in GaAs Schottky diodes induced by piezoelectric effect,” Appl. Phys. Lett., vol. 59, no. 10, pp. 1191–1193, 1991.
[111] J. Zhou, Y. Gu, P. Fei, W. Mai, Y. Gao, R. Yang, G. Bao and Z. L. Wang, “Flexible Piezotronic Strain Sensor,” Nano Lett., vol. 8, no. 9, pp. 3035, 2008.
[112] J. Zhou, Y. Gu, P. Fei, W. Mai, Y. Gao, R. Yang, G. Bao and Z. L. Wang, “Flexible Piezotronic Strain Sensor,” Nano Lett., vol. 8, no. 9, pp. 3035, 2008.
[113] P. Gao, Z. Z. Wang, K. H. Liu, Z. Xu, W. L. Wang, X. D. Bai and E. G. Wang, “Photoconducting response on bending of individual ZnO nanowires,” J. Mat. Chem., vol. 19, pp. 1002–1005, 2009.
[114] X. Wang, J. Zhou, J. Song, J. Liu, N. Xu and Z. L. Wang, “Piezoelectric Field Effect Transistor and Nanoforce Sensor Based on a Single ZnO Nanowire,” Nano Lett., vol. 6, no. 12, pp. 2768–2772, 2006.
[115] Y. K. Su, S. M. Peng, L. W. Ji, C. Z. Wu, W. B. Cheng and C. H. Liu, “Ultraviolet ZnO Nanorod Photosensors,” Langmuir, vol. 26, pp. 603–606, 2010.
[116] L. W. Ji, S. M. Peng, J. S. Wu, W. S. Shih, C. Z. Wu and I. T. Tang, “Effect of seed layer on the growth of well-aligned ZnO nanowires,” J. Phys. Chem. Solids., vol. 70, pp. 1359–1362, 2009.
[117] B. Xu and Z. Cai, “Trial-manufacture and UV-blocking property of ZnO nanorods on cotton fabrics,” J. Appl. Polymer Sci., vol. 108, pp. 3781–3786, 2008.
[118] K. Yu, Z. Jin, X. Liu, Z. Liu and Y. Fu, “Synthesis of size-tunable ZnO nanorod arrays from NH3•H2O/ZnNO3 solutions,” Mater. Lett., vol. 61, pp. 2775–2778, 2007.
[119] Z. Wang, X. F. Qian, J. Yin and Z. K. Zhu, “Large-scale fabrication of tower-like, flower-like, and tube-like ZnO arrays by a simple chemical solution route,” Langmuir, vol. 20, pp. 3441–3448, 2004.
[120] K. W. Lee, K. Y. Heo and H. J. Kim, “Photosensitivity of solution-based indium gallium zinc oxide single-walled carbon nanotubes blend thin film transistors,” Appl. Phys. Lett., vol. 94, pp. 102112, 2009.
[121] S. M. Peng, Y. K. Su, L. W. Ji, S. J. Young, C. Z. Wu, C. N. Tsai, W. C. Chao, W. B. Cheng and C. J. Huang, “Photoconductive Gain and Low-Frequency Noise Characteristics of ZnO Nanorods” Electrochem. Solid State Lett., vol. 14, no. 3, pp. J13–J15, 2011.
[122] B. Sun, R. L. Peterson, H. Sirringhaus and K. Mori, “Low-Temperature Sintering of In-Plane Self-Assembled ZnO Nanorods for Solution-Processed High-Performance Thin Film Transistos,” J. Phys. Chem. C, vol. 111, no. 51, pp. 18831–18835, 2007.
[123] H. E. Unalan, Y. Zhang, P. Hiralal, S. Dalal, D. Chu, G. Eda, K. B. K. Teo, M. Chhowalla, W. I. Milne, and G. A. J. Amaratung, “Zinc oxide nanowire networks for macroelectronic devices,” Appl. Phys. Lett., vol. 94, pp. 163501, 2009.
[124] K. H. Tam, C. K. Cheung, Y. H. Leung, A. B. Djurisic, C. C. Ling, C. D. Beling, S. Fung, W. M. Kwok, W. K. Chan, D. L. Phillips, L. Ding and W. K. Ge, “Defects in ZnO Nanorods Prepared by a Hydrothermal Method” J. Phys. Chem. B vol. 110, pp. 20865, 2006.
[125] H. S. Bae and S. Im, “Ultraviolet detecting properties of ZnO-based thin film transistors,” Thin Solid Films, vol. 469–470, pp. 75– 79, 2004.