III-V nitride semiconductors, driven by solid-state lighting applications, are nowadays widely spread in optoelectronics industry. These materials exhibit exceptional figures of merit, which make them well suited for high performance light emitters. For instance, blue light emitting diodes with 80% wall-plug-efficiency have been demonstrated, as well as blue and green laser diodes with impressive performance. This is primarily due to the very large material gain of InGaN/GaN quantum wells (QWs). On the other hand, III-nitride semiconductors are also promising for near-infrared applications thanks to negligible absorption in this spectral range related to low free carrier concentration and reduced two-photon process. Furthermore, those materials can be epitaxially grown on silicon substrates offering thereby a potential platform for integrated 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 be obtained in two-dimensional photonic crystal cavities designed at 1.5 m wavelength. This allowed us achieving efficient second and third harmonic generations. We also fabricated 1D nanobeam photonic structures in which a single InGaN QW is embedded. Thanks to high emission coupling factor, inherent to such a geometry, and to the large material gain of InGaN/GaN QW, we observed lasing action under continuous wave optical pumping at room-temperature. We will eventually highlight the importance of surface states in GaN photonic structures through a careful study of microdisk optical resonators.
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