Efficient near-infrared light emission and optical gain in Si quantum dots based on silicon oxynitride
multilayer structures
Rui Huang1, Zhenxu Lin1, Zewen Lin1, Jun Xu2, Kunji Chen2
1
School of Materials Science and Engineering, Hanshan Normal University, Guangdong, China
Email:[email protected]
2
School of Electronic Science and Engineering, Nanjing University, Jiangsu, China
In the past decade, Si-based light sources compatible with the mainstream complementary metal-oxide
semiconductor technology have attracted a great deal of interest owing to their potential application in
monolithic Si optoelectronic integrated circuits[1–3]. To engineer Si into a more efficient light-emitting
material, different approaches such as low-dimensional Si systems have been developed[3–5].
In our work, efficient near-infrared (NIR) luminescent Si quantum dots were fabricated by very high
frequency plasma enhanced chemical vapor deposition followed by thermal annealing of Si-rich Si
oxynitride and Si oxynitride multilayer structures. The analyses of the photoluminescence (PL), PL
excitation spectra, the infrared absorption spectra and X-ray photoelectron spectra indicate that the
photoexcited carriers for the enhanced NIR emission mainly originate in the quantum confined Si QDs,
while their radiative recombination occurs in the surface states related to N-Si-O bonds. On the other hand, it
is interesting to found that increasing the nitrogen content from 1% to 21% in the Si oxynitride can increase
the O-Si-N bonding states as well as the faster radiative recombination rates and thus significantly enhance
the NIR emission by more than an order of magnitude. Based on the above experimental results, Si
oxynitride multilayer structures were designed for obtaining efficient NIR emission and optical gain. In the
multilayer stuctures, Si-rich Si oxynitride sublayers were used to fabricate dense Si quantum dots, while Nrich Si oxynitride sublayers were employed to provide enough N-Si-O bonding states. It is found that the
NIR emission is remarkably enhanced by using the multilayer structures. To measure the optical gain
coefficient, the geometry structure of SiNx/Si QDs based SiNxOy multilayer/SiO2 strip-loaded waveguide was
fabricated, and the light emission was detected by VSL technique, as shown in Fig. 1. According to the onedimensioned amplifier model, the net optical gain coefficient g was estimated to be as high as 172 cm-1 at
760 nm as revealed in Fig. 2. The present results demonstrate that the Si QDs based SiNxOy multilaye system
can be a very competitive candidate in the applications of photonics and optoelectronics.
Fig1. The geometry structure of SiNx/Si QDs based SiNxOy multilayer/SiO2 strip-loaded waveguide.
Fig2. The ASE intensity at wavelength of 760 nm as a function of the excitation length for Si QDs based SiNxOy
multilayer.
Acknowledgments
This work was supported by National Natural Science Foundation of China (Nos. 61274140) and NSF of
Guangdong Province (2015A030313871).
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Presentation Method (Keynote / Invited / Regular Oral / Poster):
Invited