Blue Electroluminescent Al₂O₃/Tm₂O₃ Nanolaminate Films Fabricated by Atomic Layer Deposition on Silicon.

Yao Liu,Li Yang,Zhongtao Ouyang,Jiaming Sun,Yang Yang

doi:10.3390/nano9030413

Abstract

Realization of a silicon-based light source is of significant importance for the future development of optoelectronics and telecommunications. Here, nanolaminate Al2O3/Tm2O3 films are fabricated on silicon utilizing atomic layer deposition, and intense blue electroluminescence (EL) from Tm3+ ions is achieved in the metal-oxide-semiconductor structured luminescent devices based on them. Precise control of the nanolaminates enables the study on the influence of the Tm dopant layers and the distance between every Tm2O3 layer on the EL performance. The 456 nm blue EL from Tm3+ ions shows a maximum power density of 0.15 mW/cm2. The EL intensities and decay lifetime decrease with excessive Tm dopant cycles due to the reduction of optically active Tm3+ ions. Cross-relaxation among adjacent Tm2O3 dopant layers reduces the blue EL intensity and the decay lifetime, which strongly depends on the Al2O3 sublayer thickness, with a critical value of ~3 nm. The EL is attributed to the impact excitation of the Tm3+ ions by hot electrons in Al2O3 matrix via Poole–Frenkel mechanism.

Highlights

Traditional electronic integrated circuits have been facing with a bottleneck in terms of power consumption, speed, and signal crosstalk as the communication frequency and bandwidth rise to a higher level
The Tm2O3 films deposited by Atomic layer deposition (ALD) can be crystalized into Tm2O3 phase even without annealing, while the Al2O3 films are amorphous after annealing at 800 ◦C
Blue EL is demonstrated from nanolaminate Al2O3/Tm2O3 MOS-structured light-emitting devices (MOSLEDs) fabricated by ALD

Summary

Introduction

Traditional electronic integrated circuits have been facing with a bottleneck in terms of power consumption, speed, and signal crosstalk as the communication frequency and bandwidth rise to a higher level. One possible solution is the optoelectronic integration which realizes photonic technologies on silicon chips [1,2,3,4]. Aiming for the realization of compact Si-based optoelectronics, electroluminescence (EL) from RE3+ ions has been extensively reported in many compounds, such as SiNx, TiO2, and ZnO [12,13,14,15]. Similar devices based on Al2O3 nanofilms present much lower working voltage, and comparable efficiency in our previous study, while their EL performance needs more exploration [18,19]. Tm3+ ions have present efficient blue emissions in various matrixes including ZnS, ZnO, fluorophosphate, and many other oxides and fluorides [20,21,22,23]. Using Tm-doped Al2O3 might exploit the merits of both oxides to realize efficient blue EL from Tm3+ ions

Methods

Results

Conclusion