Improving dielectric nano-resonator-based antireflection coatings for photovoltaics

Published: September 19, 2018

Author(s)

Dongheon Ha, Nikolai B. Zhitenev

Abstract

We demonstrate optical and electrical property enhancement of solar cells using a variety of dielectric nano-resonator array coatings. First, we study close-packed silicon dioxide (SiO2) nano-resonator arrays on top of silicon (Si) and gallium arsenide (GaAs) solar cells. From macroscale measurements and calculations, we find that absorptivity of solar cells can be improved by 20 % due to the resonant couplings of excited whispering gallery modes and the thin-film antireflection effect. Next, we image photocurrent enhancement at the nanoscale via near-field scanning photocurrent microscopy (NSPM). Strong local photocurrent enhancement is observed over each nano-resonator at wavelengths corresponding to the whispering gallery mode excitation. Finally, for better optical coupling to solar cells, we explore hybrid nano- resonator arrays combining multiple materials such as silicon dioxide, silicon nitride, and titanium dioxide. Due to higher number of photonic modes within such hybrid coatings, absorptivity is enhanced by more than 30 % in a Si solar cell.
Proceedings Title: Proceedings of SPIE
Volume: 10730
Conference Dates: August 19-23, 2018
Conference Location: San Diego, CA
Conference Title: SPIE Optics and Photonics
Pub Type: Conferences

Keywords

Antireflection coatings, nanospheres, nanoresonators, whispering gallery modes, absorptivity enhancements, photocurrent enhancements, near-field scanning optical microscopy (NSOM), near- field scanning photocurrent microscopy (NSPM)
Created September 19, 2018, Updated November 10, 2018