The electroluminescence mechanism of Er3+ in different silicon oxide and silicon nitride environments

Abstract

Rare earth doped metal-oxide-semiconductor (MOS) structures are of great interest for Si-based light emission. However, several physical limitations make it difficult to achieve the performance of light emitters based on compound semiconductors. To address this point, in this work the electroluminescence (EL) excitation and quenching mechanism of Er-implanted MOS structures with different designs of the dielectric stack are investigated. The devices usually consist of an injection layer made of SiO2 and an Er-implanted layer made of SiO2, Si-rich SiO2, silicon nitride, or Si-rich silicon nitride. All structures implanted with Er show intense EL around 1540 nm with EL power efficiencies in the order of 2 × 10−3 (for SiO2:Er) or 2 × 10−4 (all other matrices) for lower current densities. The EL is excited by the impact of hot electrons with an excitation cross section in the range of 0.5–1.5 × 10−15 cm−2. Whereas the fraction of potentially excitable Er ions in SiO2 can reach values up to 50%, five times lower values were observed for other matrices. The decrease of the EL decay time for devices with Si-rich SiO2 or Si nitride compared to SiO2 as host matrix implies an increase of the number of defects adding additional non-radiative de-excitation paths for Er3+. For all investigated devices, EL quenching cross sections in the 10−20 cm2 range and charge-to-breakdown values in the range of 1–10 C cm−2 were measured. For the present design with a SiO2 acceleration layer, thickness reduction and the use of different host matrices did not improve the EL power efficiency or the operation lifetime, but strongly lowered the operation voltage needed to achieve intense EL.

Energy Transfer Under Electrical Excitation and Enhanced Electroluminescence in the Nanolaminate Yb,Er Co‐Doped Al2O3 Films

“…Many Si‐related materials have been researched as the matrix for Er 3+ ions to exploit their NIR emissions . Although progress on photoluminescence (PL) has been intensively reported, their electroluminescence (EL) performance is still far from application . For the oxides with moderate bangaps such as ZnO and TiO 2 , a high‐resistance acceleration layer is needed while the recombination and leakage currents due to the abundant grain boundaries restrict the efficiency and reliability .…”

Effect of hydrogen passivation on the photoluminescence of Tb ions in silicon rich silicon oxide films

“…It is also worth mentioning that according to a recent study of SRSO:Er films, the fraction of optically active Er 3þ ions in SRSO does not exceed 10%. 14 Also from this point of view, optical activation of "dark" ions is the most probable explanation of our observations. So far, it has been shown that the number of emitted photons increases upon passivation as a result of reduced non-radiative recombination, which is manifested by two effects: (1) longer Tb 3þ lifetime in the 5 D 4 excited state and (2) optical activation of "dark" ions.…”

“…12 Moreover, efficient light emission from Er-doped SRSN thin films has been recently demonstrated. 13,14 As in the case of SRSO, the main motivation for exploring these new host materials is the improvement of the electrical properties, which is important from the point of view of application in electrically driven light sources. 15 Despite different approaches and materials which have been used for fabrication of Si-based light sources, there are some general physical problems limiting their emission efficiency.…”

Electroluminescence from metal-oxide-semiconductor devices with erbium-doped CeO2 films on silicon

“…[1][2][3][4][5][6] As the natural oxide of silicon, SiO 2 is the most preferred host for Er 3þ ions. However, the EL from Erdoped SiO 2 (SiO 2 :Er) suffers from uncomfortably high driven voltages and EL quenching due to the excellent insulation of SiO 2 host and electron trapping, respectively.…”