Cuprous halides semiconductors as a new means for highly efficient light-emitting diodes.

Doyeol Ahn,Seoung-Hwan Park

doi:10.1038/srep20718

Doyeol Ahn, Seoung-Hwan Park

Open Access

https://doi.org/10.1038/srep20718

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Abstract

In group-III nitrides in use for white light-emitting diodes (LEDs), optical gain, measure of luminous efficiency, is very low owing to the built-in electrostatic fields, low exciton binding energy, and high-density misfit dislocations due to lattice-mismatched substrates. Cuprous halides I-VII semiconductors, on the other hand, have negligible built-in field, large exciton binding energies and close lattice matched to silicon substrates. Recent experimental studies have shown that the luminescence of I-VII CuCl grown on Si is three orders larger than that of GaN at room temperature. Here we report yet unexplored potential of cuprous halides systems by investigating the optical gain of CuCl/CuI quantum wells. It is found that the optical gain and the luminescence are much larger than that of group III-nitrides due to large exciton binding energy and vanishing electrostatic fields. We expect that these findings will open up the way toward highly efficient cuprous halides based LEDs compatible to Si technology.

Highlights

Researches on the cuprous halides semiconductors have been focused on the following areas over the past decade: (1) spectroscopic and theoretical studies of band structures[26,27,28,29,30,31,32,33], (2) photoluminescence studies of I-VII quantum dots embedded in NaCl crystals and glasses[22,24,25,33], (3) surface studies of the growth mechanisms involved in the hetero epitaxy, and single crystal and poly crystal layer growth on Si and GaAs23,35–40
We report the theoretical study of an optical gain and the luminescence of I-VII CuI/CuCl quantum well structures on Si substrates in high efficiency light-emitting device for the first time
It is observed that the optical gain and the luminescence of cuprous halides CuI/CuCl and CuBr/CuCl quantum wells (QWs) would be much higher than those of III-V nitride layers or II-VI ZnO/MgZnO QWs due to the inherent strong excitonic effects and negligible electrostatic fields within the active layers

Summary

Introduction

We report the theoretical study of an optical gain and the luminescence of I-VII CuI/CuCl quantum well structures on Si substrates in high efficiency light-emitting device for the first time. It is observed that the optical gain and the luminescence of cuprous halides CuI/CuCl and CuBr/CuCl QWs would be much higher than those of III-V nitride layers or II-VI ZnO/MgZnO QWs due to the inherent strong excitonic effects and negligible electrostatic fields within the active layers.

Results

Conclusion