Group III-element wurtzite nitride semiconductors : issues from materials science up to quantum optics. 14th Journées de la Matière Condensée (JMC14) and the 25th Conference of the Condensed Matter Division of the EPS (CMD25) Paris 2014
Résumé
The group III wurtzite nitrides have been revolutionizing the physics of semiconductors for more than two decades after that high quality materials could be grown and silicon n-type and magnesium p-type were realized at the end of the eighties. Based on this, candela class blue light emitting diodes and blue lasers were realized and commercialized. These triggered solid-state lighting and Blu-Ray DVD technology. Besides this massive arrival of optical devices on the market, a lot of basic physics phenomena inherent to the wurtzite symmetry were discovered or clarified, at least quantitatively framed. This was, and still is, of paramount importance for improving the performances of the nitride-based devices. I will review the different steps that paved the way of this breakthroughs and I will discuss the important issues that still have to be overcome in the next years: filling the green gap and realizing high luminosity amber or red light-emitting diodes in the one hand, designing and growing ultra violet light emitters in the other hand. The drawbacks inherent to the materials such as Auger non-radiative recombination processes will be discussed as well as the potentialities of growth on high Miller index surfaces for bypassing the deleterious Quantum Confined Stark Effect, for reducing the dislocation densities and for improving the performances of the generations of devices in the next years. The Nano-LEDs based on one-dimensional nitride crystals will be discussed as well as Nano lasers. Then, I will show results obtained regarding nitride quantum dots and single photon emitters, which are now grown on a large variety of surfaces, sometimes embedded into micro-cavities. At the end I will dedicate a few minutes to the presentation of boron nitride, a layered compound. Its physics is becoming a hot topics and one of the pioneers of the growth of nitrides speaks of it in terms of " the next guy".