Efficient Er/O‐Doped Silicon Light‐Emitting Diodes at Communication Wavelength by Deep Cooling

Abstract

A silicon light source at the communication wavelength is the bottleneck for developing monolithically integrated silicon photonics. Doping silicon with erbium and oxygen ions is considered one of the most promising approaches to produce silicon light sources. However, this method suffers from a high concentration of defects in the form of nonradiative recombination centers at the interface between the crystalline silicon and large Er2O3/ErSi1.7 precipitates during the standard rapid thermal treatment. Here, a deep cooling process is applied to suppress the growth of these precipitates by flushing the high‐temperature Er/O‐doped silicon substrates with helium gas cooled in liquid nitrogen. The resultant light‐emitting efficiency at room temperature is enhanced by two orders of magnitude in comparison with that of the sample treated via standard rapid thermal annealing. The deep‐cooling‐processed Si samples are further processed into light‐emitting diodes. Bright electroluminescence with a main spectral peak at 1536 nm is also observed from the silicon‐based diodes with the external quantum efficiency reaching ≈0.8% at room temperature. Based on these results, the development of electrically driven silicon optical amplifiers or even lasers at communication wavelengths is promising for monolithically integrated silicon photonics.

Polycrystalline Er-doped Y3Ga5O12 nanofilms fabricated by atomic layer deposition on silicon at a low temperature and the exploration on electroluminescence performance

“…13 To overcome these obstacles, the focus has shifted to alternative host materials and/or fabrication methods to develop suitable Si-based matrices with more excitable Er 3+ ions. 14,15…”

Efficient Er/O Doped Silicon Photodiodes at Communication Wavelengths by Deep Cooling

“…This observation is consistent with our recent finding that photoluminescence from the deepcooling-processed samples is two orders of magnitude stronger than the RTA-processed ones. [31] In Figure 3b, the dark current density for both samples first drops exponentially due to the dominance of the exponential terms in Equation ( 2). The current later levels off at lower temperature due to the nonexponential term in Equation ( 2) that is a power function of temperature T. From the exponential dependence, we found that the defect energy levels are located 0.27 and 0.10 eV ( = E t -E v ) above the Si valence band for the DC and RTA processed sample, respectively (see Figure 3b).…”

“…[29] The DC processed Er/O doped Si wafer will have a much longer back-transfer time since its photoluminescence efficiency is largely enhanced. [31] The DC processed Er/O doped Si waveguide photodiode may have a back transfer time possibly up to 5 × 10 −6 s, which leads to a cutoff frequency 1 2 1 2 3.14 5 10 30 kHz bt bt 6…”

“…[28,36] Recently, we employed a deep cooling (DC) process to treat the Er/O implanted silicon. [31] The processed samples exhibit a strong photoluminescence at room temperature, two orders of magnitude higher than the samples treated by standard RTA process. In this work, we explore the possibility to use Er/O doped silicon treated by the DC process for high-performance photodetection at communication wavelengths.…”

“…[25,26] Although silicon hyper doped with silver was made into photodiodes, [27] doping silicon with erbium (often with oxygen) [28][29][30] is particularly interesting for photodetection since Er/O doped silicon can be also potentially made into silicon light sources at communication wavelength. [31][32][33][34][35] Traditionally, Er/O doped silicon suffers from Er/O precipitation after standard rapid thermal annealing (RTA), which results in strong nonradiative recombination. [36][37][38] Consequently, the RTA-treated Er/O silicon cannot emit or detect photons at communication wavelengths efficiently at room temperature.…”