Theoretical and experimental evaluation of multilayer porous silicon structures for enhanced erbium up-conversion luminescence

TL;DR

This study combines theoretical simulations and experimental fabrication to enhance erbium up-conversion luminescence in multilayer porous silicon structures, demonstrating significant emission improvements through photonic band engineering.

Contribution

It introduces a novel approach integrating transfer matrix simulations with experimental porous silicon photonic crystals to boost erbium emission via slow-light effects.

Findings

Absorption coefficient increases by over 22% broadly and 400% narrowly.

Maximum 26.6-fold enhancement of Er$^{3+}$ emission at 550 nm.

Photonic band edge positioning affects emission intensity non-monotonically.

Abstract

The enhancement of Er$^{3+}$-based up-conversion for photovoltaics in multilayer porous silicon photonic structures is considered theoretically and experimentally. Transfer matrix simulations are used to assess the increased photonic density of states that results from the slowing of energy propagation at the short-wavelength edge of one-dimensional photonic band gaps. An indirect calculation of Er$^{3+}$ absorption enhancement within slow-light modes is then used to illustrate an increase in absorption over the bulk value: the effective absorption coefficient is shown to increase by more than 22% over a broad spectral region and by more than 400% over a narrow region. Erbium-doped porous silicon photonic crystals are fabricated with the photonic band edge coincident with the $^{4}I_{15/2} \rightarrow^{4}I_{13/2}$ Er$^{3+}$ transition. Challenges in fabrication and the results of compositional analysis are discussed. An angular-dependent photoluminescence measurement demonstrates emission intensity that varies non-monotonically with the position of the photonic band edge. A maximum of 26.6$\times$ enhancement of Er$^{3+}$ emission intensity is observed for the 550-nm transition, with lower enhancement factors seen for longer wavelengths.