Highly Luminescent <formula formulatype="inline"><tex Notation="TeX">$a\hbox{-SiO}_{\rm x} \langle \hbox{Er} \rangle/\hbox{SiO}_{2}/\hbox{Si}$</tex></formula> Multilayer Structure

Abstract

We have fabricated highly luminescent samples with erbium-doped amorphous silicon suboxide $(a\hbox{-SiO}_{x} \langle \hbox{Er}\rangle)$ layers on $\hbox{SiO}_{2}/\hbox{Si}$ substrates. The layers are designed to provide a resonance with large modal overlap with the active material and with low quality factor (Q-factor) at 1540 nm. Also, the structure has higher Q-factor resonances in the wavelength range between 800 and 1000 nm. Within this range, strong light emission from $a\hbox{-SiO}_{x}$ defect-related radiative centers and emission from the $\hbox{Er}^{3+}\,{}^{4}{ \rm I}_{11/2} - ^{4}{\rm I}_{15/2}$ optical transition (980 nm) are observed. A twofold and fourfold improvement in photoluminescence (PL) intensity are achieved in the wavelength ranges between 800 and 1000 nm and between 1500 and 1600 nm (region of $\hbox{Er}^{3+}\,{}^{4}{\rm I}_{13/2} - {}^{4}{\rm I}_{15/2}$ transition), respectively, when compared to the $a\hbox{-SiO}_{x} \langle \hbox{Er} \rangle$ active material deposited directly on Si substrate. The latter higher PL intensity enhancement is apparently caused by optical pumping at 980 nm (higher Q-factor) with subsequent emission from the ${}^{4}{\rm I}_{15/2}$ level in the low Q-factor resonance at 1540 nm. Further, five times increase of this emission at 1540 nm is obtained after optimized temperature annealing. The temperature-induced quenching in the PL intensity indicates distinct deactivation energies related to different types of Er centers which are more or less coupled to defects depending on the thermal treatment temperature

Keywords

• Photonics materials
• optical properties of photonics materials
• oxide materials