- Nano Express
- Open Access
Horizontal transfer of aligned Si nanowire arrays and their photoconductive performance
© Zhang et al.; licensee Springer. 2014
- Received: 6 October 2014
- Accepted: 25 November 2014
- Published: 9 December 2014
An easy and low-cost method to transfer large-scale horizontally aligned Si nanowires onto a substrate is reported. Si nanowires prepared by metal-assisted chemical etching were assembled and anchored to fabricate multiwire photoconductive devices with standard Si technology. Scanning electron microscopy images showed highly aligned and successfully anchored Si nanowires. Current-voltage tests showed an approximately twofold change in conductivity between the devices in dark and under laser irradiation. Fully reversible light switching ON/OFF response was also achieved with an ION/IOFF ratio of 230. Dynamic response measurement showed a fast switching feature with response and recovery times of 10.96 and 19.26 ms, respectively.
- Si nanowires
- Horizontal transfer
- Photoconductive performance
Physical properties of one-dimensional (1D) materials are quite different from those of bulk materials because of their distinct features such as high surface-to-volume ratio and quantum confinement effect [1–3]. Therefore, 1D materials, especially 1D semiconductor materials, have drawn much attention during the past decades [4–6]. Silicon nanowires (Si NWs), as a fundamental material in microelectronics, are one of the most attractive 1D semiconductor materials [7–11]. Si NWs have been considered in various potential applications such as in optoelectronics [3, 12], electronic devices , and energy conversion and storage [14–16]. Bottom-up [17, 18] and top-down techniques [11, 19, 20] are the most common synthesis methods for Si NWs. However, NWs prepared with these techniques are mostly vertically aligned; thus, studying their electron transport features and applications in a variety of devices is a key experimental challenge [21–23].
The main challenge is generally to transfer vertical NWs to a defined position laterally and anchor them with metal electrodes. The most common transfer method mainly involves two steps [3, 22]. In the first step, NWs are separated from the growth substrate and dispersed in a volatile solvent. A drop of this solvent is then casted onto the target substrate. In the second step, lithography is used to define the electrode windows, followed by metal deposition and lift-off techniques. However, in this case, NWs are randomly arranged on the substrate. Finding a device with NWs that bridge metal contacts at both ends is time consuming. Moreover, fabricating a device with multiple aligned NWs using the aforementioned method is quite difficult. Several new methods and specific equipment of assembly of nanowires are reported recently [23–27]. Lieber et al. developed a nanocombing technique that yields arrays with >98.5% of the NWs aligned to within ±1° of the combing direction . Javey et al. used a special print assembled apparatus to print NWs aligned to a receiver substrate [24, 25]. Yu et al. used a blown-bubble thin film from a solvent containing Si NWs and then stamped a substrate onto the bubble to transfer Si NWs . They transferred uniformly aligned and controlled density NWs onto wafers with a diameter of at least 200 mm. Vertical transfer of Si NW array on glass was also demonstrated by other researchers . In the current study, a simple approach to assemble large-scale and highly aligned Si NW arrays horizontally onto a target substrate surface is proposed. Moreover, multiwire photoconductive devices were fabricated with the assembled NWs. The photoresponse measurements showed a rapid switching property (10.96 and 19.26 ms for the response and recovery times, respectively) and a high ION/IOFF ratio (230). The NW assembly and device fabrication process were easily implemented and cost-effective, i.e., without specific equipment or installation. The proposed method could be a potential candidate for developing large-scale multiwire devices on a flexible substrate.
Metal-assisted chemical etching (MACE) method  was used to fabricate Si NWs. P-type Si(100) wafers (resistivity ρ < 0.01 Ω · cm) were first cleaned before etching. The wafers were rinsed for several times with deionized (DI) water and then dipped into boiling piranha solution [H2SO4 (95% to 98%) and H2O2 (30%) at a volume ratio of 3:1] for 3 min to remove metallic and organic residues. The wafers were immersed in diluted hydrofluoric acid solution [DI water:HF (10:1 by volume ratio), 40%] for 30 s to remove native oxide. The as-cleaned samples were etched in MACE solution [0.04 M AgNO3 and HF (40%) at a volume ratio of 3:1]. Etching was performed in a water bath at 40°C for 2.5 h with an etching rate of 20 μm/h. All chemicals were of analytical reagent grade and purchased from Sinopharm Chemical Regent Co., Ltd, Beijing, China. In the MACE process, Ag ions were reduced to an Ag dendritic film on a Si wafer, which catalyzed the etching of Si to finally form vertical Si NWs . Ag dendrites formed in the MACE procedure were removed in diluted nitric acid (5 M), rinsed with DI water, and dried naturally.
To confirm that aligned Si NW array devices were successfully fabricated, the photoconductive response of the devices was measured using SUSS MicroTec Test Systems (SÜSS MicroTec AG, Garching, Germany) and Agilent B1500A Semiconductor Device Analyzer (Agilent Technologies, Santa Clara, USA). An 808-nm laser diode with a power density of approximately 0.1 W/mm2 was used. Current-voltage (I-V) characteristics were examined with voltage scanning from -1 to 1 V. Light switching ON/OFF response of the device was measured under a fixed voltage of 1 V. Laser was chopped by an optical chopper (Stanford Research SR540 Optical Chopper, Stanford Research Systems, Sunnyvale, USA) at 3 Hz. All measurements were performed at room temperature.
where t 0 and t are the initial and final recovery times, and τ is the characteristic time constant, that is, lifetime. Idark is the dark current, and ΔI is the current amplitude. Accosting to this equation, the lifetime of carriers was extracted from the recovery curve in Figure 4c, and it is determined to be 7.05 ms.
A simple technique for horizontal transfer of aligned Si NW arrays onto a defined substrate has been demonstrated. Multiwire photoconductive devices were fabricated and tested. The fabricated devices exhibited a twofold change in conductivity between light and dark states. The devices also showed a fully reversible light ON/OFF switching response. High response time (10.96 ms) and recovery time (19.26 ms) were also achieved. The proposed technique provides a facile and cost-effective way to study properties of NWs and planar multiwire device applications.
This work was supported in part by the National Thousand Talents Program of China, the bilateral collaboration project between the Chinese Academy of Sciences and Japan Society for the Promotion of Science (Grant no GJHZ1316), the National Natural Science Foundation of China (Grant nos. 61176013 and 61177038), the Beijing Natural Science Foundation (Grant no. 2142031), the Beijing Municipal Science and Technology Commission project (Grant no. Z141100003814002), the Major State Basic Research Development Program of China (Grant nos. 2013CB632103 and 2011CBA00608), and the National High-Technology Research and Development Program of China (Grant nos. 2012AA012202 and 2011AA010302).
- Sun MT, Zhang ZL, Wang PJ, Li Q, Ma FC, Xu HX: Remotely excited Raman optical activity using chiral plasmon propagation in Ag nanowires. Light-Sci Appl 2013, 2: e112. 10.1038/lsa.2013.68View ArticleGoogle Scholar
- Zhang CQ, Li CB, Liu Z, Zheng J, Xue CL, Zuo YH, Cheng BW, Wang QM: Enhanced photoluminescence from porous silicon nanowire arrays. Nanoscale Res Lett 2013, 8: 277. 10.1186/1556-276X-8-277View ArticleGoogle Scholar
- Hochbaum AI, Chen RK, Delgado RD, Liang WJ, Garnett EC, Najarian M, Majumdar A, Yang PD: Enhanced thermoelectric performance of rough silicon nanowires. Nature 2008, 451: 163–167. 10.1038/nature06381View ArticleGoogle Scholar
- Li CB, Usami K, Mizuta H, Oda S: Growth of Ge-Si nanowire heterostructures via chemical vapor deposition. Thin Solid Films 2011, 519: 4174–4176. 10.1016/j.tsf.2011.02.005View ArticleGoogle Scholar
- Boukai AI, Bunimovich Y, Tahir-Kheli J, Yu JK, Goddard WA, Heath JR: Silicon nanowires as efficient thermoelectric materials. Nature 2008, 451: 168–171. 10.1038/nature06458View ArticleGoogle Scholar
- Lee EK, Yin L, Lee Y, Lee JW, Lee SJ, Lee J, Cha SN, Whang D, Hwang GS, Hippalgaonkar K, Majumdar A, Yu C, Choi BL, Kim JM, Kim K: Large thermoelectric figure-of-merits from SiGe nanowires by simultaneously measuring electrical and thermal transport properties. Nano Lett 2012, 12: 2918–2923. 10.1021/nl300587uView ArticleGoogle Scholar
- Akihama Y, Hane K: Single and multiple optical switches that use freestanding silicon nanowire waveguide couplers. Light-Sci Appl 2012, 1: e16. 10.1038/lsa.2012.16View ArticleGoogle Scholar
- Cui Y, Duan XF, Hu JT, Lieber CM: Doping and electrical transport in silicon nanowires. J Phys Chem B 2000, 104: 5213–5216.View ArticleGoogle Scholar
- Li CB, Krali E, Fobelets K, Cheng BW, Wang QM: Conductance modulation of Si nanowire arrays. Appl Phys Lett 2012, 101: 222101. 10.1063/1.4768692View ArticleGoogle Scholar
- Rathi SJ, Smith DJ, Drucker J: Guided VLS growth of epitaxial lateral Si nanowires. Nano Lett 2013, 13: 3878–3883. 10.1021/nl401962qView ArticleGoogle Scholar
- Weisse JM, Marconnet AM, Kim DR, Rao PM, Panzer MA, Goodson KE, Zheng XL: Thermal conductivity in porous silicon nanowire arrays. Nanoscale Res Lett 2012, 7: 554. 10.1186/1556-276X-7-554View ArticleGoogle Scholar
- Das K, Samanta S, Kumar P, Narayan KS, Raychaudhuri AK: Fabrication of single Si nanowire metal–semiconductor-metal device for photodetection. Ieee T Electron Dev 2014, 61: 1444–1450.View ArticleGoogle Scholar
- Schmidt V, Riel H, Senz S, Karg S, Riess W, Gosele U: Realization of a silicon nanowire vertical surround-gate field-effect transistor. Small 2006, 2: 85–88. 10.1002/smll.200500181View ArticleGoogle Scholar
- Krali E, Durrani ZAK: Seebeck coefficient in silicon nanowire arrays. Appl Phys Lett 2013, 102: 143102. 10.1063/1.4800778View ArticleGoogle Scholar
- Jeon M, Kamisako K: Synthesis and characterization of silicon nanowires using tin catalyst for solar cells application. Mater Lett 2009, 63: 777–779. 10.1016/j.matlet.2009.01.001View ArticleGoogle Scholar
- Cui LF, Ruffo R, Chan CK, Peng HL, Cui Y: Crystalline-amorphous core-shell silicon nanowires for high capacity and high current battery electrodes. Nano Lett 2009, 9: 491–495. 10.1021/nl8036323View ArticleGoogle Scholar
- Artoni P, Pecora EF, Irrera A, Priolo F: Kinetics of Si and Ge nanowires growth through electron beam evaporation. Nanoscale Res Lett 2011, 6: 162. 10.1186/1556-276X-6-162View ArticleGoogle Scholar
- Wang YW, Schmidt V, Senz S, Gosele U: Epitaxial growth of silicon nanowires using an aluminium catalyst. Nat Nanotechnol 2006, 1: 186–189. 10.1038/nnano.2006.133View ArticleGoogle Scholar
- Fu YQ, Colli A, Fasoli A, Luo JK, Flewitt AJ, Ferrari AC, Milne WI: Deep reactive ion etching as a tool for nanostructure fabrication. J Vac Sci Technol B 2009, 27: 1520–1526. 10.1116/1.3065991View ArticleGoogle Scholar
- Huang ZP, Geyer N, Werner P, de Boor J, Gosele U: Metal-assisted chemical etching of silicon: a review. Adv Mater 2011, 23: 285–308. 10.1002/adma.201001784View ArticleGoogle Scholar
- Mulazimoglu E, Coskun S, Gunoven M, Butun B, Ozbay E, Turan R, Unalan HE: Silicon nanowire network metal–semiconductor-metal photodetectors. Appl Phys Lett 2013, 103: 083114. 10.1063/1.4819387View ArticleGoogle Scholar
- Rojo MM, Calero OC, Lopeandia AF, Rodriguez-Viejo J, Martin-Gonzalez M: Review on measurement techniques of transport properties of nanowires. Nanoscale 2013, 5: 11526–11544. 10.1039/c3nr03242fView ArticleGoogle Scholar
- Yao J, Yan H, Lieber CM: A nanoscale combing technique for the large-scale assembly of highly aligned nanowires. Nat Nanotechnol 2013, 8: 329–335. 10.1038/nnano.2013.55View ArticleGoogle Scholar
- Yerushalmi R, Jacobson ZA, Ho JC, Fan Z, Javey A: Large scale, highly ordered assembly of nanowire parallel arrays by differential roll printing. Appl Phys Lett 2007, 91: 203104. 10.1063/1.2813618View ArticleGoogle Scholar
- Fan ZY, Ho JC, Jacobson ZA, Yerushalmi R, Alley RL, Razavi H, Javey A: Wafer-scale assembly of highly ordered semiconductor nanowire arrays by contact printing. Nano Lett 2008, 8: 20–25. 10.1021/nl071626rView ArticleGoogle Scholar
- Yu GH, Cao AY, Lieber CM: Large-area blown bubble films of aligned nanowires and carbon nanotubes. Nat Nanotechnol 2007, 2: 372–377. 10.1038/nnano.2007.150View ArticleGoogle Scholar
- Li CB, Fobelets K, Liu C, Xue CL, Cheng BW, Wang QM: Ag-assisted lateral etching of Si nanowires and its application to nanowire transfer. Appl Phys Lett 2013, 103: 183102. 10.1063/1.4826930View ArticleGoogle Scholar
- Peng KQ, Yan YJ, Gao SP, Zhu J: Dendrite-assisted growth of silicon nanowires in electroless metal deposition. Adv Funct Mater 2003, 13: 127–132. 10.1002/adfm.200390018View ArticleGoogle Scholar
- Kim J, Bahk JH, Hwang J, Kim H, Park H, Kim W: Thermoelectricity in semiconductor nanowires. Phys Status Solidi-R 2013, 7: 767–780. 10.1002/pssr.201307239View ArticleGoogle Scholar
- Bae J, Kim H, Zhang XM, Dang CH, Zhang Y, Choi YJ, Nurmikko A, Wang ZL: Si nanowire metal-insulator-semiconductor photodetectors as efficient light harvesters. Nanotechnology 2010, 21: 095502. 10.1088/0957-4484/21/9/095502View ArticleGoogle Scholar
- Chuo HX, Wang TY, Zhang WG: Optical properties of ZnSxSe1-x alloy nanostructures and their photodetectors. J Alloy Compd 2014, 606: 231–235.View ArticleGoogle Scholar
- Zhang G, Zhang YW: Thermal conductivity of silicon nanowires: From fundamentals to phononic engineering. Phys Status Solidi-R 2013, 7: 754–766. 10.1002/pssr.201307188View ArticleGoogle Scholar
- Hussain AA, Pal AR, Patil DS: An efficient fast response and high-gain solar-blind flexible ultraviolet photodetector employing hybrid geometry. Appl Phys Lett 2014, 104: 193301. 10.1063/1.4876450View ArticleGoogle Scholar
- Tamang R, Varghese B, Mhaisalkar SG, Tok ES, Sow CH: Probing the photoresponse of individual Nb2O5 nanowires with global and localized laser beam irradiation. Nanotechnology 2011, 22: 115202. 10.1088/0957-4484/22/11/115202View ArticleGoogle Scholar
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