Exploration of the green electroluminescence from Al2O3/Ho2O3 nanolaminate films fabricated by atomic layer deposition on silicon

Abstract

Green electroluminescence (EL) at 548 nm is obtained from the silicon-based metal-oxide-semiconductor light-emitting devices (MOSLEDs) based on the Al 2 O 3 /Ho 2 O 3 nanolaminate films fabricated by atomic layer deposition. The emerald green EL from Ho 3+ ions presents a maximum power density of 0.2 mW/cm 2 , and the excitation cross section up to 4.8 × 10 −16 cm 2 , which is attributed to the impact excitation of the Ho 3+ ions by hot electrons in Al 2 O 3 matrix via Poole–Frenkel mechanism. The critical distance for cross relaxation between Ho 2 O 3 dopant layers is ~3.0 nm, concerning both the EL intensities and the lifetime characterizations, which is consistent with previous reports. The difference resulting in the lower excitation efficiency from these Al 2 O 3 /Ho 2 O 3 MOSLEDs is speculated to originate from the non-radiative cross-relaxation within the Ho 3+ ions due to the abundant energy levels between the excited and ground states. • Electroluminescence from Al 2 O 3 /Ho 2 O 3 nanolaminates is realized on Si substrate. • The emerald green electroluminescence shows a maximum power density of 0.2 mW/cm 2 . • The excitation cross section ranges among 1.8 to 4.8 × 10 −16 cm 2 . • Exploration on distance among dopants layers reveals a critical thickness of ~3 nm. • Nonradiative cross-relaxation restricts the efficiency and lifetime of Ho emissions.