White light emission from silicon nanoparticles

TL;DR

This paper demonstrates that silicon nanoparticles approximately 200 nm in size can efficiently emit white light through resonant excitation, with ultrashort emission lifetimes, advancing silicon's potential in integrated photonic applications.

Contribution

It introduces a novel method to achieve efficient white light emission from silicon nanoparticles at nanoscale sizes using resonant excitation, with significantly reduced emission lifetime.

Findings

White light emission achieved at ~200 nm silicon nanoparticles.

Ultrashort emission lifetime of ~52 ps demonstrated.

Efficient excitation with ultralow laser energy (~40 pJ).

Abstract

As one of the most important semiconductors, silicon (Si) has been used to fabricate electronic devices, waveguides, detectors, and solar cells etc. However, its indirect bandgap hinders the use of Si for making good emitters1. For integrated photonic circuits, Si-based emitters with sizes in the range of 100-300 nm are highly desirable. Here, we show that efficient white light emission can be realized in spherical and cylindrical Si nanoparticles with feature sizes of ~200 nm. The up-converted luminescence appears at the magnetic and electric multipole resonances when the nanoparticles are resonantly excited at their magnetic and electric dipole resonances by using femtosecond (fs) laser pulses with ultralow low energy of ~40 pJ. The lifetime of the white light is as short as ~52 ps, almost three orders of magnitude smaller than the state-of-the-art results reported so far for Si (~10 ns). Our finding paves the way for realizing efficient Si-based emitters compatible with current semiconductor fabrication technology, which can be integrated to photonic circuits.