Broadband Antireflection Coatings Made of Resonant Submicron- and Micron-Sized SiGe Particles Grown on Si Substrates

Alexander A Shklyaev,Andrei V Tsarev

doi:10.1109/jphot.2021.3081100

Abstract

The solid-state dewetting phenomenon was used to obtain submicron- and micron-sized SiGe particle arrays by the Ge deposition on Si(100) substrates. Their transmission and reflection spectra were measured and numerically modeled by the FDTD method. They exhibit resonance effects in broad infrared spectral ranges, depending on the particle size. The broadband antireflection property is associated with wide particle size distributions and the influence of a high-index substrate. The results show that the dewetting phenomenon provides the natural formation of arrays of particles shaped as close to a sphere segment, and they turned out to be effective as antireflection coatings.

Highlights

The use of antireflection coatings essentially improves the efficiency of various optoelectronic devices, in particular, photodetectors
The transmission and reflection spectra were obtained for Si(100) substrates coated with submicron- and micron-sized SiGe particles which were formed using the dewetting phenomenon
These minima are associated with the destructive interference of the incident EM field and the field of electric and magnetic dipole resonances generated in the dielectric SiGe particles

Summary

Introduction

The use of antireflection coatings essentially improves the efficiency of various optoelectronic devices, in particular, photodetectors. The strong effect on the reflection and transmission of EM radiation caused by coatings consisting of dielectric particles originates from the destructive interference with resonant magnetic and electric dipole modes. Calculations have shown that the positions of dipole modes coincide for disk-shaped particles with AR ~ 0.4-0.5 [34], [40], [43] Such AR values are often observed in particles formed using various methods [35]-[37], in particular, by the agglomeration of continuous layers on non-wettable surfaces [18], [20], [23], [38], [39]. The results of our numerical simulation using the FDTD method confirmed the broadband properties of the SiGe particle on Si substrates due to the strong EM resonances in particles with relative large AR values of about 0.4, despite their low Q-factor

Experimental details

Results and discussion

Conclusions