Template-assisted nanostructure fabrication by glancing angle deposition: a molecular dynamics study
© Zhang et al.; licensee Springer. 2013
Received: 24 May 2013
Accepted: 28 June 2013
Published: 5 July 2013
In the present work, we investigate the pre-existing template-assisted glancing angle deposition of Al columnar structures on Cu substrate by means of molecular dynamics simulations, with a focus on examining the effect of deposition-induced template deformation on the morphologies of the fabricated structures. Our simulations demonstrate that the pre-existing templates significantly intensify the shadowing effect, which thus facilitates the formation of columnar structures under small deposition flux. The underlying deformation modes of the templates under different deposition configurations are analyzed and are correlated to the geometrical characteristics of the columnar structures. It is found that the template height-dependent deformation behavior of the templates strongly influences the morphologies of the fabricated columnar structures. Our findings provide design and fabrication guidelines for the fabrication of one-dimensional nanostructures by the template-assisted deposition technique.
One-dimensional (1D) nanostructures, including nanopillars, nanorods, nanotubes, and nanowires, are promising building blocks for constructing nanoscale electronical and optoelectronical elements and interconnects because of their unique physical properties . In addition to the characterization, the fabrication of ordered arrays of 1D nanostructures has been one of the current research focuses of nanostructures engineering. In particular, the rotational glancing angle deposition (GLAD) has been demonstrated to be one powerful nanostructuring technique for the fabrication of columnar nanostructures in an orientation- and structure-controllable, material-independent fashion [2–6]. The rotational GLAD as a physical vapor deposition is extended from the static GLAD (oblique angle deposition) by adding azimuthal and/or polar rotations of the substrate. During the rotational GLAD process, the lateral component of deposition flux with respect to the surface normal of the substrate contributes to the formation of columnar structures due to the shadowing effect, while the rotation of the substrate eliminates the preferred orientation growth, thus controls the shape of the structures. In the past few decades, there is considerable effort of both experimental investigation and atomistic simulations taken to investigate the fundamental mechanisms of the rotational GLAD [7–11].
Since nucleated islands acting as shadowing centers are essentially required for the formation of columnar structures in the initial period of the rotational GLAD, recently placing nano-sized templates on the bare substrate is proposed to replace the nucleated islands, in such a way both deposition period and deposition flux can be reduced significantly. Most importantly, by designing the geometry and the alignment of the templates, ordered arrays of columnar structures with pre-designed shapes can be fabricated under the intensified shadowing effect [12, 13]. Although the template-assisted rotational GLAD has been demonstrated to be one promising nanostructuring technique for the fabrication of 1D nanostructures, our fundamental understanding of the deposition process, particularly the deposition-induced deformation of the templates, is still limited: will the templates deform during the deposition? If yes, what are the underlying deformation mechanisms of the templates? And how does the deformation behavior of the templates influence the geometry of the fabricated columnar structures?
In this letter, we address the above questions by performing three-dimensional molecular dynamics (MD) simulations of the template-assisted rotational GLAD of 1D Al columnar structures on Cu substrate. Our simulations demonstrate that the presence of templates significantly intensifies the shadowing effect to form 1D columnar structures when deposition flux is small, as compared to the template-free rotational GLAD. Furthermore, the morphology of the fabricated columnar structures by the template-assisted rotational GLAD strongly depends on the deformation behaviors of the templates.
Parameters for the four deposition configurations
Rotational velocity (ps−1)
Template geometry (d, s, h)
0, 0, 0
6a, 10a, 14a
6a, 10a, 14a
6a, 10a, 8a
Results and discussion
Figure 2 also shows that the morphology of the columnar structures strongly depends on the parameters of the deposition configurations. Figure 2b shows that the height distribution of the columnar structures obtained through the high template-assisted rotational GLAD is not uniform, although the heights of the templates are the same. Furthermore, slight inclination of the axial of the columnar structures is observed. For the template-assisted static GLAD, the inclination is more pronounced than the template-assisted rotational GLAD, as shown in Figure 2b. In addition, the discrepancy between the heights of the columnar structures is pronounced, and the coalescence of columnar structures occurs. A comparison between Figure 2b,c shows that the template-assisted rotational GLAD leads to a lower but more uniform columnar structures than the template-assisted static GLAD, given the same height of the templates. As compared to the high template-assisted rotational GLAD, Figure 2d shows that the morphologies of the columnar structures obtained through the low template-assisted rotational GLAD are more uniform, as the structures are mainly straight and the heights are almost the same. We note that the morphology of the columnar structures may strongly depend on the rotational velocity, which determines the coverage of deposited Al atoms in conjunction with the deposition rate. It suggests that the height of the templates has strong influence on the morphology of the columnar structures obtained through the template-assisted rotational GLAD.
In summary, we perform MD simulations of the pre-existing template-assisted rotational GLAD to investigate the influence of templates on the formation of Al columnar nanostructures on Cu substrate. Our simulation results show that under small deposition flux, the presence of the templates significantly contributes to the formation of columnar structures due to the intensified shadowing effect, while there are only islands formed during template-free rotational GLAD. As compared to the template-assisted static GLAD, the azimuthal rotation of the substrate during the template-assisted rotational GLAD leads to uniform morphologies of the formed columnar structures. Our simulations reveal the two deformation modes of dislocation mechanisms and deformation twinning that operating in the plastic deformation of the templates, which strongly influence both the morphologies of the templates and the formed columnar structures. While the formation of TBs mainly causes the shape change of the templates, the presence of ISF leads to the shear of the template by an atomic step. Furthermore, the deformation modes dominating the plastic deformation of the templates change significantly with the height of the templates.
The authors greatly acknowledge finical support of the Foundation for Innovative Research Groups of the National Natural Science Foundation of China (no. 51075088), the Doctoral Discipline Foundation for Young Teachers in the Higher Education Institutions of Ministry of Education (no. 20092302120005), the Heilongjiang Provincial Natural Science Foundation (no. E201019), and the Fundamental Research Funds for the Central Universities (grant no. HIT. NSRIF. 2014050).
- Xia YN, Yang PD, Sun YG, Wu YY, Mayers B, Gates B, Yin YD, Kim F, Yan HQ: One-dimensional nanostructures: synthesis, characterization, and applications. Adv Mater 2003, 15: 353–389. 10.1002/adma.200390087View ArticleGoogle Scholar
- Zhao YP YDX, Wang GC LTM: Designing nanostructures by glancing angle deposition. Proc SPIE 2003, 5219: 59–73. 10.1117/12.505253View ArticleGoogle Scholar
- Robbie K, Beydaghyan G, Brown T, Dean C, Adams J, Buzea C: Ultrahigh vacuum glancing angle deposition system for thin films with controlled three-dimensional nanoscale structure. Rev. Sci Instrum 2004, 75: 1089–1097. 10.1063/1.1667254View ArticleGoogle Scholar
- Hawkeye MMBMJ: Glancing angle deposition: fabrication, properties, and applications of micro- and nanostructured thin films. J Vac Sci Technol A 2007, 25: 1317. 10.1116/1.2764082View ArticleGoogle Scholar
- Zhou Y, Taima T, Miyadera T, Yamanari T, Kitamura M, Nakatsu K, Yoshida Y: Glancing angle deposition of copper iodide nanocrystals for efficient organic photovoltaics. Nano Lett 2012, 12: 4146–4152. 10.1021/nl301709xView ArticleGoogle Scholar
- Krause KM, Taschuk MT, Brett MJ: Glancing angle deposition on a roll: towards high-throughput nanostructured thin films. J Vac Sci Technol A 2013, 31: 031507. 10.1116/1.4798947View ArticleGoogle Scholar
- Kesapragada SV, Gall D: Anisotropic broadening of Cu nanorods during glancing angle deposition. Appl Phys Lett 2006, 89: 203121. 10.1063/1.2388861View ArticleGoogle Scholar
- Chen ST, Li ZC, Zhang ZJ: Anisotropic TiXSn1-XO2 nanostructures prepared by magnetron sputter deposition. Nanoscale Res Lett 2011, 6: 326. 10.1186/1556-276X-6-326View ArticleGoogle Scholar
- Backholm M, Foss M, Nordlund K: Roughness of glancing angle deposited titanium thin films: an experimental and computational study. Nanotechnology 2012, 23: 385708. 10.1088/0957-4484/23/38/385708View ArticleGoogle Scholar
- BackholmM FM, Nordlund K: Roughness scaling in titanium thin films: a three-dimensional molecular dynamics study of rotational and static glancing angle deposition. Appl Surf Sci 2013, 268: 270–273.View ArticleGoogle Scholar
- Chen SH, Liang JS, Mo YJ, Luo DF, Jiang SJ: Onset of shadowing-dominated growth of Ag films in glancing angle deposition: Kinetic Monte Carlo simulation. Appl Surf Sci 2013, 264: 552–556.View ArticleGoogle Scholar
- Patzig C, Karabacak T, Fuhrmann B, Rauschenbach B: Glancing angle sputter deposited nanostructures on rotating substrates: experiments and simulations. J Appl Phys 2008, 104: 094318. 10.1063/1.3018145View ArticleGoogle Scholar
- Bauer J, Weise M, Rauschenbach B, Geyer N, Fuhrmann B: Shape evolution in glancing angle deposition of arranged Germanium nanocolums. J Appl Phys 2012, 111: 104309. 10.1063/1.4719978View ArticleGoogle Scholar
- Cao YZ, Zhang JJ, Sun T, Yan YD, Yu FL: Atomistic study of deposition process of Al thin film on Cu substrate. Appl Surf Sci 2010, 256: 5993–5997. 10.1016/j.apsusc.2010.03.107View ArticleGoogle Scholar
- Cao YZ, Zhang JJ, Wu C, Yu FL: Effect of incident angle on thin film growth: a molecular dynamics simulation study. Thin Solid Films 2013. in press in pressGoogle Scholar
- Cai J, Ye YY: Simple analytical embedded-atom-potential model including a long-range force for fcc metals and their alloys. Phys Rev B 1996, 54: 8398–8410. 10.1103/PhysRevB.54.8398View ArticleGoogle Scholar
- Plimpton S: Fast parallel algorithms for short-range molecular dynamics. J Comput Phys 1995, 117: 1–19. 10.1006/jcph.1995.1039View ArticleGoogle Scholar
- Honeycutt JD, Andersen HC: Molecular dynamics study of melting and freezing of small Lennard-Jones clusters. J Phys Chem 1987, 91: 4950–4963. 10.1021/j100303a014View ArticleGoogle Scholar
- Stukowski A, Albe K: Dislocation detection algorithm for atomistic simulations. Modelling Simul Mater Sci Eng 2010, 18: 025016. 10.1088/0965-0393/18/2/025016View ArticleGoogle Scholar
- Stukowski A: Visualization and analysis of atomistic simulation data with OVITO - the Open Visualization Tool. Modelling Simul Mater Sci Eng 2010, 18: 015012. 10.1088/0965-0393/18/1/015012View ArticleGoogle Scholar
- Li J: AtomEye: an efficient atomistic configuration viewer. Modelling Simul Mater Sci Eng 2003, 11: 173–177. 10.1088/0965-0393/11/2/305View ArticleGoogle Scholar
- Frantz J, Rusanen M, Nordlund K, Koponen IT: Evolution of Cu nanoclusters on Cu(100). J. Phys.: Condens. Matter 2004, 16: 2995–3003. 10.1088/0953-8984/16/17/027Google Scholar
- Park HS, Gall K, Zimmerman JA: Deformation of FCC nanowires by twinning and slip. J Mech Phys Solids 2006, 54: 1862–1881. 10.1016/j.jmps.2006.03.006View ArticleGoogle Scholar
- Lee SJ, Lee BY, Cho MH: Compressive pesudoelastic behavior in copper nanowires. Phys Rev B 2010, 81: 224103.View ArticleGoogle Scholar
- Zhang JJ, Xu FD, Yan YD, Sun T: Detwinning-induced reduction in ductility of twinned copper nanowires. Chin Sci Bull 2013, 58: 684–688. 10.1007/s11434-012-5575-3View ArticleGoogle Scholar
- Zhang JJ, Sun T, Yan YD, Dong S, Li XD: Atomistic investigation of scratching-induced deformation twinning in nanocrystalline Cu. J Appl Phys 2012, 112: 073526. 10.1063/1.4757937View ArticleGoogle Scholar
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.