Nanoscale transverse Fabry-Perot resonators

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The ability to fabricate multiple resonant photodetectors, each with separately engineered wavelength sensitivity, in a single-step process has many potential applications. In this dissertation, we propose and demonstrate the use of nanoscale semiconductor fin structures surrounded by metal as efficient transverse Fabry-Perot resonators which allow one to efficiently excite in-plane resonances under surface-normal incidence. We show that these devices support strong absorption resonances that can be tuned by varying the width of the structure and use this effect to engineer devices for two potential application areas. In the first part of the dissertation, we show how we can engineer nanoscale planar multispectral image sensors based on silicon fins surrounded by metallic slits wherein the resonant wavelength of each pixel is determined by the width of the silicon fin. The same metallic structure is used for both light confinement and carrier extraction in a compact metal-semiconductor-metal (MSM) geometry. We experimentally study how close we can put two of these pixels together and how small we can make an individual pixel. We show that, in principle if the electrical properties of the devices are suitably controlled, one can engineer devices with pixel pitch down to 250 nm and pixel sizes down to 500 nm by 500 nm. In the second part of the dissertation, we use this effect to enhance the indirect absorption in germanium and engineer CMOS-compatible germanium photodetectors with high responsivity across the telecommunications bands (both C and L bands). Finally, we show that this effect can be used to engineer passive devices like novel resonant waveguide couplers that can be used to couple light efficiently from free space to both dielectric and plasmonic slot waveguides with slot widths ~ 50 nm.


Type of resource text
Form electronic; electronic resource; remote
Extent 1 online resource.
Publication date 2013
Issuance monographic
Language English


Associated with Coimbatore Balram, Krishna
Associated with Stanford University, Department of Electrical Engineering.
Primary advisor Miller, D. A. B
Thesis advisor Miller, D. A. B
Thesis advisor Brongersma, Mark L
Thesis advisor Fan, Shanhui, 1972-
Advisor Brongersma, Mark L
Advisor Fan, Shanhui, 1972-


Genre Theses

Bibliographic information

Statement of responsibility Krishna Coimbatore Balram.
Note Submitted to the Department of Electrical Engineering.
Thesis Thesis (Ph.D.)--Stanford University, 2013.
Location electronic resource

Access conditions

© 2013 by Krishna Coimbatore Balram
This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).

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