Perfect light trapping in nanoscale thickness semiconductor films with resonant back reflector and spectrum-splitting structures

TL;DR

This paper theoretically demonstrates that nanoscale semiconductor films can achieve near-perfect broadband light absorption by combining interference-based light-trapping structures with spectrum-splitting, enhancing solar energy harvesting efficiency.

Contribution

It introduces a novel approach combining interference-induced photonic localization with spectrum-splitting structures for enhanced light absorption in ultrathin semiconductor films.

Findings

Achieves nearly perfect broadband absorption in <100 nm films.

Uses interference effects in photonic crystal or metal structures.

Combines spectrum-splitting with wedge-shaped spacers for improved performance.

Abstract

The optical absorption of nanoscale thickness semiconductor films on top of light-trapping structures based on optical interference effects combined with spectrum-splitting structures is theoretically investigated. Nearly perfect absorption over a broad spectrum range can be achieved in $<100$ nm thick films on top of one-dimensional photonic crystal or metal films. This phenomenon can be attributed to interference induced photonic localization, which enhances the absorption and reduces the reflection of the films. Perfect solar absorption and low carrier thermalization loss can be achieved when the light-trapping structures with wedge-shaped spacer layer or semiconductor films are combined with spectrum-splitting structures.