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Sauletekis Semiconductor Physics Seminar
GaN micro- and nanophotonic cavities
Nicolas Grandjean (Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland)
18th May, 2019 16:00 / NFTMC D401, Saulėtekio av. 3, Vilnius
III-V nitride semiconductors are nowadays widely spread in the optoelectronic industry, which is mainly driven by the blue light emitting diode (LED). The latter is the corner-stone of white LEDs, which recently triggered the general lighting revolution. On the other hand, III-nitrides are also promising for photonics.
In this presentation, we will focus on GaN photonic crystal cavities, which are fabricated from GaN-on-silicon wafers. We will show that quality factors in excess of 40’000 can bee fabricated in two-dimensional photonic crystal cavities designed for 1.5 μm resonance. This allowed us achieving efficient second and third harmonic generations. We also fabricated nanobeam photonic structures in which a single InGaN quantum well was embedded. Thanks high β emission coupling factor, inherent to such a geometry, and the large material gain, we observed lasing action under continuous wave optical pumping at room-temperature. We will finally highlight the importance of surface states in GaN photonic structures through a careful study of microdisk optical resonators.
Come earlier for coffee, tea and sweets.