Near-Infrared Electroluminescence Based on Nd-Doped Ga₂O₃ Nanolaminates Fabricated by Atomic Layer Deposition for Optoelectronic Applications

Abstract

Near-infrared electroluminescence (EL) peaking at 1067 nm is achieved from the devices based on Ga 2 O 3 :Nd nanolaminates fabricated by atomic layer deposition on silicon. The emissions originating from intra-4f transitions in Nd 3+ ions are activated by both forward and reverse biases, with an external quantum efficiency of ∼1% and the optical power density of 10.5 mW/cm 2 . The devices operate continuously for more than 4 h and exhibit fluctuant EL emission under alternating-current excitation. Such EL is triggered by the energetic electrons accelerated via interfacial SiO x or Al 2 O 3 / TiO 2 nanolaminate layers. EL under unidirectional bias is obtained by using a 4 nm interfacial Al 2 O 3 nanofilm that sustains the electric field and energizes injected electrons, demonstrating the acceleration of electrons by high resistance layers and the carrier conduction considering interface energy barrier is indispensable for efficient EL excitation. This work provides innovative nanofilms based on Nd-doped oxides with great potential for applications in Si-based photonics and integrated optoelectronics.

Atomic Layer Deposition and Electroluminescence of Er-Doped Polycrystalline Lu3Ga5O12 Nanofilms for Silicon-Based Optoelectronics

“…The growth of atomic layer deposition (ALD) is established by the repetition of self-terminating reaction cycles, and the deposition of artificially designed thin films with a specific structure is feasible and convenient. , The atomic-scale compositional control achieved by ALD enables the fabrication of Si-based crystalline garnet nanofilms using post-annealing that are compatible with the silicon substrate (≤1200 °C) since the distance of ion migration and diffusion can be significantly reduced. , Our previous results also manifested the potential for manufacturing polycrystalline gallium garnet nanofilms at lower temperatures in comparison with others due to the substitution of Ga 3+ ions in the matrix. − So far, little achievement regarding the controllable ALD growth of Si-based LuGG nanofilms has been reported in the literature; the solid-phase reactions, the resultant crystallization, and the luminescent performance of the composite oxide nanofilms still require exploration. These oxides are compatible with the contemporary CMOS technology and would promote the development of optoelectronic integration and also lighting, amplifiers, and detectors. , …”

“…The details of the growth parameters and the characterizations were as previously reported. − ,, Briefly, different Ga 2 O 3 /Lu 2 O 3 /Er 2 O 3 nanolaminates were grown on n-type silicon substrates (phosphorous-doped, 2–5 Ω·cm) using a commercial ALD system (4 inch chamber, MNT Micro and Nanotech Co., Ltd.). Triethyl-gallium [Ga­(C 2 H 5 ) 3 , maintained at room temperature (RT)], Lu­(THD) 3 , and Er­(THD) 3 (THD: 2,2,6,6-tetramethyl-3,5-heptanedionate, both heated to 200 °C) were used as the precursors for Ga 2 O 3 , Lu 2 O 3 , and Er 2 O 3 , respectively, with ozone used as the oxidant.…”

“…The growth of atomic layer deposition (ALD) is established by the repetition of self-terminating reaction cycles, and the deposition of artificially designed thin films with a specific structure is feasible and convenient. 26,27 The atomic-scale compositional control achieved by ALD enables the fabrication of Si-based crystalline garnet nanofilms using post-annealing that are compatible with the silicon substrate (≤1200 °C) since the distance of ion migration and diffusion can be significantly reduced. 28,29 Our previous results also manifested the potential for manufacturing polycrystalline gallium garnet nanofilms at lower temperatures in comparison with others due to the substitution of Ga 3+ ions in the matrix.…”

Controllable Design of Minority Carrier Diffusion in npn Devices for Enhancing Er3+-Related Electroluminescence

“…However, cost-effective CMOS-compatible light sources are still hard to come by. Due to the stable luminescence in the ultraviolet to infrared bands, rare earth (RE) is frequently used in full-color displays, , phosphors, , and optical communication. − Among RE, erbium (Er) can emit photons at 1.54 μm through the intra-4f radiation transition from 4 I 13/2 to 4 I 15/2 , which is situated in the minimum-loss window of quartz fiber communication. − Because of this, optoelectronics will greatly benefit from the realization of the electroluminescence (EL) associated with Er 3+ ions. The thermionic collision mechanism is one of the effective ways to produce electroluminescence of Er 3+ ions at 1.54 μm. , Based on this mechanism, various light sources of Er 3+ ions have been developed, including Er-doped insulator devices, , reverse bias pn junction devices, , and electronic accelerator layer devices. − However, these Er-doped thermal electronic devices typically suffer from a high onset voltage issue that induces a strong electric field in certain areas of the device, greatly reducing the operating stability of the devices.…”

Effects of oxygen vacancies on the optical and electrical performances of silicon-based Er doped Ga2O3 films

“…Gallium oxide (Ga 2 O 3 ), as an emerging ultra-wide bandgap semiconductor, has aroused extensive interest in the areas of power devices [1,2], solar-blind photodetectors [3][4][5], and optoelectronics [6,7], due to its wide bandgap of ∼4.8 eV as well as high critical breakdown field of ∼8 MV cm −1 . For the purpose of applying Ga 2 O 3 in different devices, oxygen vacancies (V O ), as one of the most common point defects within native Ga 2 O 3 , need to play important roles [8,9].…”