Annealing temperature effect on self-assembled Au droplets on Si (111)
© Sui et al.; licensee Springer. 2013
Received: 28 October 2013
Accepted: 12 November 2013
Published: 13 December 2013
We investigate the effect of annealing temperature on self-assembled Au droplets on Si (111). The annealing temperature is systematically varied while fixing other growth parameters such as deposition amount and annealing duration clearly to observe the annealing temperature effect. Self-assembled Au droplets are fabricated by annealing from 50°C to 850°C with 2-nm Au deposition for 30 s. With increased annealing temperatures, Au droplets show gradually increased height and diameter while the density of droplets progressively decreases. Self-assembled Au droplets with fine uniformity can be fabricated between 550°C and 800°C. While Au droplets become much larger with increased deposition amount, the extended annealing duration only mildly affects droplet size and density. The results are systematically analyzed with cross-sectional line profiles, Fourier filter transform power spectra, height histogram, surface area ratio, and size and density plots. This study can provide an aid point for the fabrication of nanowires on Si (111).
KeywordsAu droplets Annealing temperature Nanowires
Recently, nanoscale particles have drawn increasing attention. For example, gold particles, as a popular nanomaterial with outstanding optoelectronic properties, have been widely used in sensor applications by the enrichment of detection range and optimization and enhancement of sensitivity [1–4]. In addition, Au particles are also attractive based on their capacity to catalyze one-dimensional (1-D) nanostructures, namely nanopillars and nanowires with lots of remarkable properties via various epitaxial growth mechanisms [5–10]. Fabrications of diverse nanowires such as GaN, ZnO, InAs, GaAs, Si, and Ge have been demonstrated using Au droplets as catalyst [11–18]. Nonetheless, given the wide range of substrates utilized, Au droplets can be successfully utilized in the fabrication of the various nanowires and many elements utilized for substrates would diffuse into gold during the fabrications of nanowires [11–18]. The design and growth of nanowires including diameter, length, and density in many cases can be determined by the size, density, and configurations of Au droplets [17, 18]. From this point, the control of Au droplet is an essential step for designing desired nanowires [19–24]. As discussed, the properties of Au droplets and approaches to the fabrication of nanowires have been widely studied; however, up to date, the systematic study on the control of Au droplets is still rarely to be studied.
In this work, gold droplets were synthesized on Si (111) substrates by the systematic variation of annealing temperature in a pulsed laser deposition (PLD) system under a chamber vacuum of 1 × 10−4 Torr. To investigate the annealing temperature effect on the fabrication of self-assembled Au droplets, each growth was performed at 50°C, 100°C, 150°C, 250°C, 350°C, 550°C, 700°C, 800°C, 850°C, 900°C, and 950°C, respectively. Initially, 1-mm-thick singular 4-in. p-type Si (111) wafers were 1 × 1 cm2 diced by a wire-sawing machine and treated with a conventional RCA clean. Each sample is degassed at 850°C for 15 min under a chamber vacuum of 1 × 10−4 Torr, and subsequently, 2-nm-thick gold films were deposited in a plasma ion-coater chamber under a pressure of 1 × 10−1 Torr at a rate of 0.05 nm/s with 3-mA ionization current. For a systematic annealing, a computer-operated recipe was run and the ramping-up rate was at 2.3°C/s under 1 × 10−4 Torr. After reaching each target annealing temperature, 30 s of annealing time was given for each sample, and finally, the temperature was quenched down immediately after finishing each growth to minimize Ostwald ripening [19, 25]. The quenching process was kept identical for all samples. An atomic force microscope (AFM) was utilized for the surface morphology characterization, and XEI software was used for analyzing the obtained data.
Results and discussion
RMS surface roughness ( R q ) of self-assembled Au droplets at corresponding annealing temperature
In brief, the annealing temperature effect on the fabrication of self-assembled Au droplets on Si (111) was studied in terms of size, density, and uniformity with AFM images, line profiles, FFT power spectra, and histograms. In general, the dimensions of Au droplets including the average height and diameter were gradually increased with the increased annealing temperature. The expansion of dimensions was accompanied by the reduction in the average density. The Au droplets fabricated below 500°C showed somewhat poor uniformities as evidenced by the FFT spectra, and the uniformity was improved between 550°C and 800°C likely due to favorable surface diffusion of adatoms induced by sufficient thermal energy. At above 850°C, the Au droplets began melting due to the lower eutectic point of Au-Si alloy, and the melting got severe as temperature was increased. With an increased deposition amount, the size of Au droplets grew much larger and the density was significantly decreased. Meanwhile, the increased annealing duration showed minor effects on the droplet size and density. This study can find applications in the fabrication of nanowires on Si (111).
This work was supported by the National Research Foundation (NRF) of Korea (no. 2011-0030821 and 2013R1A1A1007118). This research was in part supported by the research grant of Kwangwoon University in 2013.
- Tzyy-Jiann W, Cheng-Wei T, Fu-Kun L: Integrated-Optic Surface-Plasmon-Resonance Biosensor Using Gold Nanoparticles by Bipolarization Detection. IEEE Journal of Selected Topics in Quantumelectronics 2005, 11(2):493–499.View ArticleGoogle Scholar
- Chang S-J, Hsueh T-J, Chen I-C, Huang B-R: Highly sensitive ZnO nanowire CO sensors with the adsorption of Au nanoparticles. Nanotechnology 2008, 19: 175502. 10.1088/0957-4484/19/17/175502View ArticleGoogle Scholar
- Tao L, Ji'an T, Long J: The enhancement effect of gold nanoparticles as a surface modifier on DNA sensor sensitivity. Biochem Biophys Res Commun 2004, 313: 3–7. 10.1016/j.bbrc.2003.11.098View ArticleGoogle Scholar
- Yuan-Tai T, Yun-Ju Chuang Y-CW, Chung-Shi Yang M-CW, Fan-Gang T: A gold-nanoparticle-enhanced immune sensor based on fiber optic interferometry. Nanotechnology 2008, 19: 345501(1)-345501(9).Google Scholar
- Jianwei Z, Lirong Q, Yong Z, Yonghao H, Qing G, Lide Z: Catalytic growth of cubic phase ZnO nanowires with jagged surface. Micro & Nano Letters 2010, 5: 336–339. 10.1049/mnl.2010.0126View ArticleGoogle Scholar
- Kazuki N, Takeshi Y, Hidekazu T, Tomoji K: Control of magnesium oxide nanowire morphologies by ambient temperature. Appl Phys Lett 2007, 90: 233103(1)-233103(3).Google Scholar
- Igor L, Albert D, Babak N, Norman S, Pavel M: Growth habits and defects in ZnO nanowires grown on GaN/sapphire substrates. Appl Phys Lett 2005, 87: 103110(1)-103110(3).Google Scholar
- Amarilio-Burshtein I, Tamir S, Lifshitz Y: Growth modes of ZnO nanostructures from laser ablation. Appl Phys Lett 2010, 96: 103104(1)-103104(3).View ArticleGoogle Scholar
- Borchers C, Muller S, Stichtenoth D, Schwen D, Ronnin C: Catalyst − nanostructure interaction in the growth of 1-D ZnO nanostructures. J Phys Chem B 2006, 110: 1656–1660. 10.1021/jp054476mView ArticleGoogle Scholar
- Hou T, Ng Jun L, Michael K, Smith P, Pho N, Alan C, Jie H, Meyyappan M: Growth of epitaxial nanowires at the junctions of nanowalls. Science 2003, 300: 1249. 10.1126/science.1082542View ArticleGoogle Scholar
- Igor A, Yeshayahu L, Shoshana T: Growth mechanisms of amorphous SiO x nanowires. Appl Phys Lett 2007, 90: 263109 (1)-263109 (3).Google Scholar
- Sharma S, Kamins SS, Stanley Williams R: Synthesis of thin silicon nanowires using gold-catalyzed chemical vapor deposition. Appl Phys A 2005, 80: 1225–1229. 10.1007/s00339-004-3155-3View ArticleGoogle Scholar
- Kimberly A, Dick K, Knut D, Thomas M, Bernhard M, Lars S, Werner S: Failure of the vapor − liquid − solid mechanism in Au-assisted MOVPE growth of InAs nanowires. Nano Lett 2005, 5: 761–764. 10.1021/nl050301cView ArticleGoogle Scholar
- Pin Ann L, Dong L, Samantha R, Xuan P, Gao A, Mohan Sankaran R: Shape-controlled Au particles for InAs nanowire growth. Nano Lett 2012, 12: 315–320. 10.1021/nl2036035View ArticleGoogle Scholar
- Orvatinia M, Imani R: Effect of catalyst layer on morphology and optical properties of zinc-oxide nanostructures fabricated by carbothermal evaporation method. Micro & Nano Letter 2011, 6: 650–655.View ArticleGoogle Scholar
- Ryan D, Donald A, Walko , Seth A, Fortuna , Xiuling L: Realization of unidirectional planar GaAs nanowires on GaAs (110) substrates. IEEE Electron Device Letters 2012, 33: 522–524.View ArticleGoogle Scholar
- Shao YM, Nie TX, Jiang ZM, Zou J: Behavior of Au-Si droplets in Si(001) at high temperatures. Appl Phys Lett 2012, 101: 053104(1)-053104(3).Google Scholar
- Ruffino F, Romano L, Pitruzzello G, Grimaldi MG: High‒temperature annealing of thin Au films on Si: growth of SiO2 nanowires or Au dendritic nanostructures? Appl Phys Lett 2012, 100: 053102(1)-053102(5).View ArticleGoogle Scholar
- Glasner K, Otto F, Rump T, Slepcev D: Ostwald ripening of droplets: the role of migration. Euro Jnl of Applied Mathematics 2009, 20: 1–67. 10.1017/S0956792508007559View ArticleGoogle Scholar
- Chen WH, Larde R, Cadel E, Xu T, Grandidier B, Nys JP, Stiévenard D, Pareige P: Study of the effect of gas pressure and catalyst droplets number density on silicon nanowires growth, tapering, and gold coverage. J Appl Phys 2010, 107: 084902(1)-084902(7).Google Scholar
- Gottschalch V, Wagner G, Bauer J, Paetzelt H, Shirnow M: VLS growth of GaN nanowires on various substrates. J Cryst Growth 2008, 310: 5123–5128. 10.1016/j.jcrysgro.2008.08.013View ArticleGoogle Scholar
- Ji-Hyoen P, Navamathavan R, Yeom BR, Yong HR, Jin SK, Cheul RL: The growth behavior of GaN NWs on Si(111) by the dispersion of Au colloid catalyst using pulsed MOCVD. J Cryst Growth 2011, 319: 31–38. 10.1016/j.jcrysgro.2011.01.070View ArticleGoogle Scholar
- Ahl J-P, Behmenburg H, Giesen C, Regolin I, Prost W, Tegude FJ, Radnoczi GZ, Pecz B, Kalisch H, Jansen RH, Heuken M: Gold catalyst initiated growth of GaN nanowires by MOCVD. Physica Status Solidi (c) 2011, 8: 2315–2317. 10.1002/pssc.201000992View ArticleGoogle Scholar
- Seok-Hyo Y, Suthan K, Don Wook K, Jun-Ho C, Yong-Ho R, Cheul-Ro L: Synthesis of InN nanowires grown on droplets formed with Au and self-catalyst on Si(111) by using metalorganic chemical vapor deposition. J Mater Res 2010, 25: 1778–1783. 10.1557/JMR.2010.0219View ArticleGoogle Scholar
- Jian Hua Y, Elder KR, Hong G, Martin G: Theory and simulation of Ostwald ripening. Phys Rev B 1993, 47: 14110–14125. 10.1103/PhysRevB.47.14110View ArticleGoogle Scholar
- Ressel B, Prince KC, Heun S: Wetting of Si surfaces by Au–Si liquid alloys. J Appl Phys 2003, 93: 3886–3892. 10.1063/1.1558996View ArticleGoogle Scholar
- Venkatachalam DK, Fletcher NH, Sood DK, Elliman RG: Self-assembled nanoparticle spirals from two-dimensional compositional banding in thin films. Appl Phys Lett 2009, 94: 213110(1)-213110(3).View ArticleGoogle Scholar
- Wakayama Y, Tanaka S-i: Self-assembled nanocomposite structure of Si-Au system formed by liquid phase epitaxy. J Cryst Growth 1997, 181: 304–307. 10.1016/S0022-0248(97)00249-2View ArticleGoogle Scholar
- Ruffino F, Canino A, Grimaldi MG, Giannazzo F, Roccaforte F, Raineri V: Kinetic mechanism of the thermal-induced self-organization of Au/Si nanodroplets on Si(100): size and roughness evolution. J Appl Phys 2008, 104: 024310(1)-024310(7).View ArticleGoogle Scholar
- AbuWaar ZY, Zhiming MW, Lee JH, Salamo GJ: Observation of Ga droplet formation on (311)A and (511)A GaAs surfaces. Nanotechnology 2006, 17: 4037–4040. 10.1088/0957-4484/17/16/007View ArticleGoogle Scholar
- Lei G, Yusuke H, Ming-Yu L, Jiang W, Sangmin S, Sang-Mo K, Eun-Soo K, Zhiming M, Wang J, Jihoon L, Gregory J, Salamo J: Observation of Ga metal droplet formation on photolithographically patterned GaAs (100) surface by droplet epitaxy. IEEE Trans Nanotechnol 2012, 11: 985–991.View ArticleGoogle Scholar
- Jihoon L, Zhiming W, Yusuke H, Eun-Soo K, Namyoung K, Seunghyun P, Cong W, Salamo GJ: Various configurations of In nanostructures on GaAs (100) by droplet epitaxy. Cryst Eng Comm 2010, 12: 3404–3408. 10.1039/c0ce00057dView ArticleGoogle Scholar
- Lee JH, Wang ZM, Black WT, Kunets VP, Mazur YI, Salamo GJ: Spatially localized formation of InAs quantum dots on shallow patterns regardless of crystallographic directions. Adv Funct Mater 2007, 17: 3187. 10.1002/adfm.200700066View ArticleGoogle Scholar
- Lee JH, Zh M, Wang E, Kim S, Kim NY, Park SH, Salamo GJ: Self-assembled InGaAs tandem nanostructures consisting of a hole and pyramid on GaAs (311)A by droplet epitaxy. Phys Status Solidi 2010, 207: 348–353. 10.1002/pssa.200925406View ArticleGoogle Scholar
- Lee JH, Sablon K, Wang ZM, Salamo GJ: Evolution of InGaAs quantum dot molecules. J Appl Phys 2008, 103: 054301. 10.1063/1.2890149View ArticleGoogle Scholar
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