Excitation of hybrid modes in plasmonic nanoantennas coupled with GeSiSn/Si multiple quantum wells for the photoresponse enhancement in the short-wave infrared range

Hybrid structures represented by a plasmonic nanoantenna array located on the surface of GeSiSn/Si multiple quantum wells (MQWs) grown on a silicon-on-insulator (SOI) substrate by molecular-beam epitaxy were developed for applications in the short-wave infrared range. Using numerical modeling methods, the electromagnetic characteristics of metasurfaces based on aluminum nanoantennas located on the surface of GeSiSn/Si nanoheterostructures were studied. It is shown that the spectral and spatial overlap of localized plasmons in nanoantennas and waveguide modes in the semiconductor film leads to the formation of hybrid modes with a Fano-type resonance profile. The possibility of significant photoluminescence (PL) enhancement of GeSiSn/Si MQWs through the use of hybrid plasmonic structures is demonstrated. The PL enhancement reached to 250 % at the wavelength of 1.9 μm, coinciding with the maximum of the reflectance spectrum for the hybrid structure. Based on the hybrid system, represented by the plasmonic nanoantenna array on the top part of GeSiSn/Si MQWs, p-i-n photodiodes were fabricated. The photocurrent enhancement was approximately 7 times at wavelengths of 1.73 µm and 1.8 µm. The excitation of separately localized plasmons and waveguide modes is demonstrated, and their hybridization is also studied.