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

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.