Directional quantum dot emission by soft-stamping on silicon Mie resonators.

Tom Veeken,Albert Polman,Esther Alarcón-Lladó,Jorik Van De Groep,Benjamin Daiber,Harshal Agrawal,Bruno Ehrler,Erik C Garnett,Mark Aarts

doi:10.1039/d1na00630d

Tom Veeken, Albert Polman + Show 7 more

Open Access

https://doi.org/10.1039/d1na00630d

Copy DOI

Abstract

We present a soft-stamping method to selectively print a homogenous layer of CdSeTe/ZnS core–shell quantum dots (QDs) on top of an array of Si nanocylinders with Mie-type resonant modes. Using this new method, we gain accurate control of the quantum dot's angular emission through engineered coupling of the QDs to these resonant modes. Using numerical simulations we show that the emission into or away from the Si substrate can be precisely controlled by the QD position on the nanocylinder. QDs centered on a 400 nm diameter nanocylinder surface show 98% emission directionality into the Si substrate. Alternatively, for homogenous ensembles placed over the nanocylinder top-surface, the upward emission is enhanced 10-fold for 150 nm diameter cylinders. Experimental PL intensity measurements corroborate the simulated trends with cylinder diameter. PL lifetime measurements reflect well the variations of the local density of states at the QD position due to coupling to the resonant cylinders. These results demonstrate that the soft imprint technique provides a unique manner to directly integrate optical emitters with a wide range of nanophotonic geometries, with potential applications in LEDs, luminescent solar concentrators, and up- and down-conversion schemes for improved photovoltaics.

Highlights

Accurate control over the angular distribution of light emission is of great importance in many technological applications
We demonstrate accurate control over the directional emission of luminescent quantum dots selectively placed on top of resonant Si nanocylinders on a Si substrate
The quantum dots (QDs) are placed on the silicon nanostructures using a novel so stamp method that selectively prints on the top surface of the nanostructures

Summary

Introduction

Accurate control over the angular distribution of light emission is of great importance in many technological applications. Similar to the calculation for the single emitter at the center, the curves converge to the reference for large diameter, but there is no cylinder geometry where the emission reaches below the reference This means that emitters placed in the outer perimeter of the nanocylinder surface couple well to multipolar resonances that promote upward emission (see Fig. S2†). Preferential upward or downward emission can further be controlled by placing QDs selectively on the center or edge of the cylinder

Conclusions

Findings

Methods