J4 ›› 2017, Vol. 34 ›› Issue (6): 742-746.

• Semiconductor Opto-electronics • Previous Articles     Next Articles

Vertical optical coupling of AlGaN/GaN Multi-quantum Well Mid-infrared Photodetector via Two-dimensional Gold Grating

  

  • Received:2016-08-26 Revised:2016-09-29 Published:2017-11-28 Online:2017-12-11

Abstract: A two-dimensional gold grating has been studied to enhance the optical coupling of the AlGaN/GaN multi-quantum wells (MQWs) mid-infrared photodetector under normal illumination, which is insensitive to the polarization of incident light. The electric distribution and energy flow were theoretically analyzed by finite element method (FEM). It showed that the effective electric field component Ez perpendicular to the MQWs region obtained via the gold grating was two order of magnitudes higher than the Si3N4 grating. The results should be contributed mainly to the surface plasmon polariton (SPP) excited at the interface of the Au/AlGaN, and it strongly changed the direction of energy flow and vibration of electric field. When the electric field intensity of the incident light was 1 (V/m)2 with normal illumination, the effective electric field intensity was up to 0.7 (V/m)2, which will help to realize the AlGaN/GaN MQWs mid-infrared photodetector focal plane areas (FPAs).

Key words: SPP

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