High-Speed Internal Photoemission Detectors Enhanced by Grating Coupling to Surface Plasma Waves
The use of gratings to couple optical energy into surface plasma wave (SPW) modes that are confined to a metal-dielectric boundary has been extensively explored . With optimal choices of the grating period and profile, nearly 100% coupling efficiency has been achieved in wavelength ranges where the metal is normally almost totally reflecting. We report the use of this coupling to enhance the quantum efficiency of internal-photoemission detectors in which hot carriers, generated in a metal film by optical absorption, are collected by photoemission over a Schottky barrier into a semiconductor. This class of detectors is of interest as a result of its uniformity, high-speed potential, long wavelength response with binary rather than quaternary III–V compounds, and compatibility with integrated circuit fabrication techniques [2, 3, 4]. For metal-silicide/Si systems, which have been the most thoroughly explored, techniques such as back-illumination and double-pass insulator-metal overlayer structures already provide quite high absorption (> 40%) at infrared wavelengths. Surface texturing has also been used to enhance the responsivity of metal-insulator-metal tunnel junction detectors and of metal-(a-Si)-metal detectors [5,6].
KeywordsSchottky Barrier Reverse Bias Depletion Region Angular Response Surface Plasma Wave
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- 1.G. N. Zhizhin, M. A. Moskalova, E. V. Shomina and V. A. Yakovlev, in Surface Polaritons, V. M. Agranovich and D. L. Mills, Eds. (North-Holland, New York, 1982).Google Scholar
- 2.F. D. Shepherd in SPIE Proceedings 443: Infrared Detectors, W. L. Wolfe, Ed. (SPIE, 1984), p. 42.Google Scholar
- 3.W. F. Kosonocky and H. Elabd, ibid, p. 167.Google Scholar
- 7.S. R. J. Brueck, V. Diadiuk, W. Lenth and T. Jones, Appl. Phys. Lett. (May 15, 1985, to be published).Google Scholar