1 research outputs found
Atomic Layer Engineering of Er-Ion Distribution in Highly Doped Er:Al<sub>2</sub>O<sub>3</sub> for Photoluminescence Enhancement
For
the past decade, erbium-doped integrated waveguide amplifiers
and lasers have shown excellent potential for on-chip amplification
and generation of light at the important telecommunication wavelength
regime. However, Er-based integrated devices can only provide small
gain per unit length due to the severe energy-transfer between the
Er-ions at high concentration levels. Therefore, active ion concentrations
have been limited to <1% levels in these devices for optimal performance.
Here, we show an efficient and practical way of fabricating Er-doped
Al<sub>2</sub>O<sub>3</sub> with Er-concentration as high as ∼3.5%
before concentration quenching starts to limit the C-band emission
in our material. The Er-doped Al<sub>2</sub>O<sub>3</sub> was fabricated
by engineering the distribution of the Er-ions in Al<sub>2</sub>O<sub>3</sub> with the atomic layer deposition (ALD) technique. By choosing
a proper precursor for the fabrication of Er<sub>2</sub>O<sub>3</sub>, the steric hindrance effect was utilized to increase the distance
between the Er-ions in the lateral direction. In the vertical direction,
the distance was controlled by introducing subsequent Al<sub>2</sub>O<sub>3</sub> layers between Er<sub>2</sub>O<sub>3</sub> layers.
This atomic scale control of the Er-ion distribution allows us to
enhance the photoluminescence of our Er:Al<sub>2</sub>O<sub>3</sub> material by up to 16 times stronger when compared to the case where
the Er-concentration is ∼0.6%. In addition, long lifetime of
approximately 5 ms is preserved in the Er-ions even at such high concentration
levels. Thus, our optimized ALD process shows very promising potential
for the deposition of optical gain media for integrated photonics
structures