Improving the Luminescent Properties of Atomic Layer Deposition Eu:Y2O3 Thin Films through Optimized Thermal Annealing

Marion Scarafagio,Alban Ferrier,Alexandre Tallaire,Michel Cassir,Marie-Hélène Chavanne,Philippe Goldner,Armelle Ringuedé,Diana Serrano

doi:10.1002/pssa.201900909

Abstract

Crystalline rare‐earth (RE)‐doped Y2O3 films are an attractive system for a wide range of photonics applications including quantum technologies which aim at harnessing optical or spin transitions with long coherence times to achieve new functionalities such as quantum storage or information processing. Herein, atomic layer deposition (ALD) of Eu‐doped Y2O3 thin films with improved optical properties is presented. A crucial post‐treatment step to obtain high‐quality films is annealing at elevated temperatures (>900 °C). However, the main drawback of this approach is the formation of unwanted parasitic phases due to reaction at the interface with the substrate, especially with silicon. In this article, this issue is discussed for different kinds of substrates and buffer layers. The use of such modified substrates allows advantageously extending the maximum thermal treatment up to 1150 °C without being limited by interface reactions. It is demonstrated that the emission of the 5D0 → 7F2 transition for Eu3+ in Y2O3 film can be as narrow as that of bulk materials when optimized thermal treatments and a thin undoped Y2O3 buffer layer are used. Thus, a versatile method to reduce the impact of the substrate–film interface on the optical properties is proposed.

Highlights

The development of low cost, compact, highly integrated optical devices will greatly benefit a large range of applications including optical sensing, telecommunication, spectroscopy and quantum technologies (QT)
On the other hand, are less explored they could potentially open the way for on-chip integration with other devices such as light sources or detectors. [8,9] To achieve that, a key requirement is the growth of thin crystalline films of rare-earth-doped oxides with low levels of impurities and defects
We demonstrated for rare earth (RE):Y2O3 10 nm-thin films that a high deposition temperature and post treatment annealing above 900°C are key parameters for optimizing the luminescent properties

Summary

Introduction

The development of low cost, compact, highly integrated optical devices will greatly benefit a large range of applications including optical sensing, telecommunication, spectroscopy and quantum technologies (QT). In the framework of QTs, rare earth (RE) doped thin films appear as promising systems along other solid-state materials such as NV centres in diamond or quantum dot semiconductors. On the other hand, are less explored they could potentially open the way for on-chip integration with other devices such as light sources or detectors. [8,9] To achieve that, a key requirement is the growth of thin crystalline films of rare-earth-doped oxides with low levels of impurities and defects. The development of high-quality films can benefit a broader community since new applications of Y2O3 have recently emerged such as catalyst for biodiesel production, wastewater treatment, or anti-corrosion. The development of high-quality films can benefit a broader community since new applications of Y2O3 have recently emerged such as catalyst for biodiesel production, wastewater treatment, or anti-corrosion. [10--12]

Results

Discussion

Conclusion