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Advances in Optical Technologies
Volume 2011 (2011), Article ID 504530, 8 pages
Research Article

Impact of Nanograting Phase-Shift on Light Absorption Enhancement in Plasmonics-Based Metal-Semiconductor-Metal Photodetectors

1Electron Science Research Institute, Edith Cowan University, Joondalup, WA 6027, Australia
2Department of Electrical and Computer Engineering, Curtin University, Perth, WA 6845, Australia
3School of Photonics Science, Gwangju Institute of Science and Technology (GIST), 261 Cheomdan-gwagiro (Oryong-dong), Buk-gu, Gwangju 500-712, Republic of Korea
4Department of Nanobio Materials and Electronics, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712, Republic of Korea
5Department of Information and Communications, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712, Republic of Korea

Received 3 March 2011; Accepted 10 May 2011

Academic Editor: Mikhail Vasiliev

Copyright © 2011 Narottam Das et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The finite difference time-domain (FDTD) method is used to simulate the light absorption enhancement in a plasmonic metal-semiconductor-metal photodetector (MSM-PD) structure employing a metal nanograting with phase shifts. The metal fingers of the MSM-PDs are etched at appropriate depths to maximize light absorption through plasmonic effects into a subwavelength aperture. We also analyse the nano-grating phase shift and groove profiles obtained typically in our experiments using focused ion beam milling and atomic force microscopy and discuss the dependency of light absorption enhancement on the nano-gratings phase shift and groove profiles inscribed into MSM-PDs. Our simulation results show that the nano-grating phase shift blue-shifts the wavelength at which the light absorption enhancement is maximum, and that the combined effects of the nano-grating groove shape and phase shift degrade the light absorption enhancement by up to 50%.