Blue electroluminescent Al 2 O 3 /tm 2 o 3 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 Al 2 O 3 /Tm 2 O 3 films are fabricated on silicon utilizing atomic layer deposition, and intense blue electroluminescence (EL) from Tm 3+ 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 Tm 2 O 3 layer on the EL performance. The 456 nm blue EL from Tm 3+ ions shows a maximum power density of 0.15 mW/cm 2 . The EL intensities and decay lifetime decrease with excessive Tm dopant cycles due to the reduction of optically active Tm 3+ ions. Cross-relaxation among adjacent Tm 2 O 3 dopant layers reduces the blue EL intensity and the decay lifetime, which strongly depends on the Al 2 O 3 sublayer thickness, with a critical value of ~3 nm. The EL is attributed to the impact excitation of the Tm 3+ ions by hot electrons in Al 2 O 3 matrix via Poole–Frenkel mechanism.