Wavelength-Shifted Yellow Electroluminescence of Si Quantum-Dot Embedded 20-Pair SiNx/SiOx Superlattice by Ostwald Ripening Effect

Abstract

Yellow electroluminescence (EL) of a 20-pair Si-rich SiN x /SiO x superlattice is demonstrated by plasma-enhanced chemical vapor deposition (PECVD) and annealing process. After annealing at 900 C for 30 min, two photoluminescence (PL) peaks at 480 and 570 nm are observed to blue-shift the PL wavelength, and the corresponding peak intensity is enhanced due to the self-aggregation of Si quantum dots (QDs). When increasing the annealing temperature to 1050 C, the PL peaks caused by the aggregated Si-QDs in SiN x and SiO x layers red-shift to 500 and 600 nm, thereby shifting the PL peak wavelength to 520 nm. Such a wavelength red-shifting phenomenon is mainly attributed to the formation of large Si-QDs due to the Ostwald ripening effect. The turn-on voltage and the V -I slope of the ITO/SiN x /SiO x /p-Si/Al LED device are 200 V and 15.5 kV/mA with FowlerNordheim (FN) tunneling assistant carrier transport under an effective barrier height of 1.3 eV. Maximum output-power-current slope of 0.2 W/A at power conversion efficiency of 10 À6 is detected.

Luminescence from Si-Implanted SiO2-Si3N4 Nano Bi-Layers for Electrophotonic Integrated Si Light Sources

“…Moreover, this band matches a combination of different relative contributions by a variety of well-known centers observed in silicon nitrides and oxynitrides [5,24,25,26,27]. Emission within the same wavelengths is likely to be caused by the contribution of emission from centers introduced by nitrogen dangling bonds in SiNxOy films [26,27] (this is the only significant contribution to luminescence in sample R ), transitions between the silicon nitride conduction band and defect levels of the type ≡Si0 [24], and defect levels of either the type ≡Si− [27] or ≡Si0 [25].…”

Si-QD Synthesis for Visible Light Emission, Color Conversion, and Optical Switching

“…Lin et al also observed the PL at the same wavelength from Si + -implanted SiOx film [78]. In addition, similar PL peak was also observed in SiOx/SiNx superlattice [79]. Tohmon et al claimed that the PL of NOV defects in oxygendeficient high-purity silica glass at 459 nm [80].…”

“…Particularly, these defect-related PL emissions are usually located between green-and blue-light regions. The PL spectra of the weak oxygen bond (WOB, denoted as O-O) and neutral oxygen vacancy (NOV, denoted as O3≡Si-Si≡O3) are ranged between 415 and 455 nm [77][78][79][80][81][82]. As a supporting evidence, Cheang-Wong et al obtained the visible PL peak at 415 nm in Ir 2+ -doped silica glass owing to the contribution of the WOB defect [77].…”

Liquid Type Nontoxic Photoluminescent Nanomaterials for High Color Quality White-Light-Emitting Diode

“…The obtained luminous efficiency values were found to be 16.2 lm/W and 14.5 lm/W for GQD neutral white LEDs and GQD/P-Si QD for warm white LEDs, respectively. In comparison to the liquid-type sample, the PL emission peaks of the dispensing samples are red-shifted because of QD self-aggregation, which is caused due to the absence of a carrier solution [44–46]. Further, the small particles are aggregate into larger particles, diversifying energy transfer [47–50].…”