| AVS 57th International Symposium & Exhibition | |
| Thin Film | Thursday Sessions |
| Session TF-ThP |
| Session: | Thin Film Poster Session II |
| Presenter: | A. Lalany, University of Alberta, Canada |
| Authors: | A. Lalany, University of Alberta, Canada R.T. Tucker, University of Alberta, Canada M.D. Fleischauer, National Institute for Nanotechnology (NRC Canada) M.J. Brett, University of Alberta, Canada |
| Correspondent: | Click to Email |
Glancing Angle Deposition (GLAD)1 thin films are increasingly used in optical and sensor devices that benefit from the unique refractive properties or ultra-high surface area. Extending the use of GLAD films to energy devices, epitomised by the fields of photovoltaics2 and fuel cell catalysis3, increases the complexity in desired film requirements. High electrical conductivity along the length of GLAD structures - normal to the substrate plane - is necessary in order to exploit the high surface area of GLAD films in electronic devices. To date, GLAD has been applied to a variety of metals and conductive oxides4-6, and preliminary trends outline a relationship between the angle of incident flux, film density and in-plane resistivity. More specifically, it has been found that as the oblique deposition angle increases, the in-plane resistivity also increases. This relationship has been attributed to a decrease in film density resulting in diminished conductive pathways. Electrical anisotropy has also been observed, with differing in-plane resistivity for parallel and perpendicular directions with respect to the nanocolumns formed.4-6 A thorough study of both in-plane and through-post conductivity as a function of film composition, morphology, porosity, and crystallinity / phase is required to understand the complex interplay between film morphology and corresponding electrical properties. Quantifying differences between vertical and lateral-plane characteristics of GLAD films requires expanding on established techniques for in-plane measurements (which largely neglect morphological effects) and tailoring techniques to apply directly to GLAD films. It has been found that external boundaries begin to dominate standard bulk scattering mechanisms as film thickness decreases, resulting in an inverse relationship between film thickness and resistivity.7 Subsequently, the extensive boundaries present in GLAD films between and within individual features can result in complex electrical behaviour. We will quantify the variations in both in-plane and through-post conductivity through the use of direct and indirect experimental approaches, and relate the results to deposition parameters suitable for forming GLAD films of desirable conductivity.
[1] M.M. Haweye et al., J. Vac. Sci. Technol. A, 25, 1317, (2007).
[2] N. Li et al., Appl. Phys. Lett., 95, 123309, (2009).
[3] A. Bonakdarpour et al., Appl. Catal. A., 349, 110 (2008).
[4] J. Lintymer et al., Surf. & Coat. Tech. 174-175, 316, (2003).
[5] K.D. Harris et al., Adv. Funct. Mater., 18, 2147, (2008).
[6] D. Vick et al., J. Vac. Sci. Technol. A, 24, 156, (2006).
[7] A.F. Mayada, M. Shatzkes, Phys. Rev. B, 1, 1382 (1970).