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Proceedings Paper

Intersubband transitions in the THz using GaN quantum wells (Conference Presentation)
Author(s): Caroline B. Lim; Akhil Ajay; Catherine Bougerol; Jörg Schörmann; David A. Browne; Mark Beeler; Eva Monroy

Paper Abstract

Research on III-nitride intersubband (ISB) transitions in the THz spectral range is motivated by the large LO-phonon energy of GaN, which should permit device operation with limited thermal interference, and at infrared wavelengths inaccessible to other III-V compounds due to Reststrahlen absorption. A main challenge to extend the polar GaN-ISB technology towards the THz region comes from the polarization-induced internal electric field, which imposes an additional confinement that increases the energetic distance between the electronic levels. In order to surmount this constraint, we propose alternative multi-layer quantum well designs that create a pseudo-square potential profile with symmetric wavefunctions [1]. The robustness of these designs and their integration in device architectures requiring tunneling transport will be discussed. An alternative approach to obtain square potential profiles is the use of nonpolar crystallographic orientations. In this contribution, we present an experimental study of THz ISB transitions in m-plane GaN/AlGaN quantum wells grown on free-standing m-GaN [2]. For Al contents below 15%, such structures can be grown without epitaxially-induced extended defects. We demonstrate nonpolar quantum wells which display ISB transitions in the 7-10 THz band, and we will discuss the effect of the doping density in the quantum wells on the transition energy and line width. Finally, we will present a comparative study using silicon and germanium as n-type dopants. [1] M. Beeler, et al., Appl. Phys. Lett. 105, 131106 (2014) [2] C.B. Lim, et al., Nanotechnology 26, 435201 (2015); Nanotechnology 27, 145201 (2016).

Paper Details

Date Published: 19 April 2017
PDF: 1 pages
Proc. SPIE 10104, Gallium Nitride Materials and Devices XII, 101040C (19 April 2017); doi: 10.1117/12.2252455
Show Author Affiliations
Caroline B. Lim, CEA Grenoble (France)
Akhil Ajay, CEA-Grenoble (France)
Catherine Bougerol, Institut NÉEL (France)
Jörg Schörmann, Justus-Liebig-Univ. Giessen (Germany)
David A. Browne, CEA-Grenoble (France)
Mark Beeler, CEA Grenoble (France)
Eva Monroy, CEA Grenoble (France)

Published in SPIE Proceedings Vol. 10104:
Gallium Nitride Materials and Devices XII
Jen-Inn Chyi; Hiroshi Fujioka; Hadis Morkoç; Yasushi Nanishi; Ulrich T. Schwarz; Jong-In Shim, Editor(s)

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