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Inter-subband optics at 1.55 µm in GaN-based nanostructures - Physics and applications

Maria Tchernycheva 1Houssaine Macchadani 1Laurent Nevou 1Juliette Mangeney 1François H Julien 1Prem K. Kandaswamy 2Alexander Wirthmüller 2Eva Monroy 2Alon Vardi 3Shmuel Schacham 3Gad Bahir 3Gianmauro Pozzovivo 4Sebastien Golka 4Gottfried Strasser 4

1. Institut Electronique Fondamentale, Université Paris-Sud, Orsay 91405, France
2. CEA Grenoble, Département de Recherche Fondamentale sur la Matière Condensée/SP2M, Grenoble 38054, France
3. Department of Electrical Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel
4. Zentrum für Mikro und Nanostrukturen, TUW, Floragasse 7, Wien 1040, Austria


Thanks to their large conduction band offset (up to 1.75 eV for GaN/AlN), III-nitride nanostructures in the form of quantum dots (QD) or quantum wells (QW) offer great prospects for ultrafast intersubband devices operating at room temperature in the near-infrared spectral range. Nitride intersubband devices are intrinsically very fast because of the subpicosecond absorption recovery time due to enhanced electron-LO phonon interaction in these highly ionic materials. In this talk, we will report on recent achievements in terms of GaN/AlGaN-based intersubband physics, devices and technology. 

As a first example of QW intersubband device, we will show how electron tunneling between coupled quantum wells can be applied to the fabrication of fast electro-optical modulators at 1.3-1.55 µm wavelengths. Then, we will present recent experiments on a new type of ultrafast detectors based on the quantum cascade concept. Finally, we will discuss the progress towards near-infrared lasers and amplifiers based on the observation of intersubband light emission from GaN/AlN quantum wells at a wavelength as short as 2 µm.  

GaN/AlN QDs are also of great interest for intersubband devices, namely because of the achievable large QD density (a few 1012 cm-2) and of the expected narrow linewidth of intraband transitions due to the slow-down of the dephasing mechanisms. We will describe recent resonant Raman scattering experiments which reveal an intraband light emission at a record short wavelength of 1.5 µm and allow estimating the intraband linewidth of single QDs. We have also performed pump-probe femtosecond measurements which show the extremely short intraband lifetime (165 fs) while the intraband saturation intensity (0.27 pJ/µm2) is one order of magnitude smaller than that measured in QWs. These results open prospects for ultrafast saturable absorbers and all-optical switches based on GaN QDs for telecommunication applications.


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Presentation: Invited oral at E-MRS Fall Meeting 2009, Symposium C, by Maria Tchernycheva
See On-line Journal of E-MRS Fall Meeting 2009

Submitted: 2009-05-26 16:58
Revised:   2009-06-15 14:34