Photoresponse of GeSiSn/Si p–i–n photodiodes coupled with photonic crystals with microcavities

The GeSiSn/Si p–i–n photodiodes coupled with photonic crystal structures containing an array of microresonators in the form of supercells (3×3) and (5×5) were developed. The electromagnetic characteristics of the microresonators in the semiconductor waveguide layer were studied using numerical simulation methods. In the reflection spectrum of the periodic array of microresonators of the (3×3) type, multiple asymmetric resonance features of the Fano type are observed, caused by the excitation of waveguide modes. It is shown that at the main resonance frequencies, a local amplification of the electric field in the central part of the microresonators occurs. The integral intensity coefficients of the electric field in the two-dimensional problem of scattering of the photonic crystal mode on microresonators of the (3×3) and (5×5) types were calculated. It is shown that in the near infrared range, amplification occurs at frequencies corresponding to the eigenmodes of the microresonator up to 7 times compared to a defect-free crystal. In the photocurrent spectrum for the supercell structure (5×5), a narrow line with a width of 1 nm is observed at a wavelength of 1.55 μm, corresponding to the excitation of the microresonator mode. An increase in the photoluminescence signal was also observed compared to the original epitaxial structure, reaching up to 4 and up to 8 times, respectively, for structures with (3×3) and (5×5) supercells.

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