Université de Neuchâtel

Latest developments in GaN-based quantum devices for infrared optoelectronics

Monroy, Eva ; Guillot, Fabien ; Leconte, Sylvain ; Nevou, Laurent ; Doyennette, Laeticia ; Tchernycheva, Maria ; Julien, François H. ; Baumann, Esther ; Giorgetta, Fabrizio R. ; Hofstetter, Daniel

In: Journal of Materials Science : Materials in Electronics, 2008, vol. 19, no. 8-9, p. 821-827

In this work, we summarize the latest progress in intersubband devices based on GaN/AlN nanostructures for operation in the near-infrared. We first discuss the growth and characterization of ultra-thin GaN/AlN quantum well and quantum dot superlattices by plasma-assisted molecular-beam epitaxy. Then, we present the performance of nitride-based infrared photodetectors and electro-optical...

Université de Neuchâtel

Photodetectors based on intersubband transitions using III-nitride superlattice structures

Hofstetter, Daniel ; Baumann, Esther ; Giorgetta, Fabrizio R. ; Théron, Ricardo ; Wu, Hong ; Schaff, William J. ; Dawlaty, Jahan ; George, Paul A. ; Eastman, Lester F. ; Rana, Farhan ; Kandaswamy, Prem K. ; Leconte, Sylvain ; Monroy, Eva

In: Journal of Physics: Condensed Matter, 2009, vol. 21, no. 17, p. 174208 1-12

We review our recent progress on the fabrication of near-infrared photodetectors based on intersubband transitions in AlN/GaN superlattice structures. Such devices were first demonstrated in 2003, and have since then seen a quite substantial development both in terms of detector responsivity and high speed operation. Nowadays, the most impressive results include characterization up to 3 GHz using...

Université de Neuchâtel

MBE growth of nitride-based photovoltaic intersubband detectors

Monroy, Eva ; Guillot, Fabien ; Leconte, Sylvain ; Bellet-Amalric, Edith ; Baumann, Esther ; Giorgetta, Fabrizio R. ; Hofstetter, Daniel ; Nevou, Laurent ; Tchernycheva, Maria ; Doyennette, Laeticia ; Julien, François H. ; Remmele, T. ; Albrecht, M.

In: Superlattices and Microstructures, 2006, vol. 40, no. 4-6, p. 418-425

In this work, we present the plasma-assisted molecular-beam epitaxial growth of quantum well infrared photodetector (QWIP) structures, including the Si-doped GaN/AlN short-period superlattice of the active region, conductive AlGaN claddings and integration of the final device. The growth of Si-doped GaN/AlN multiple quantum well (QW) structures is optimized by controlling substrate temperature,...

Université de Neuchâtel

GaN/AlN electro-optical modulator prototype at telecommunication wavelengths

Baumann, Esther ; Giorgetta, Fabrizio R. ; Hofstetter, Daniel ; Guillot, Fabien ; Leconte, Sylvain ; Bellet-Amalric, Edith ; Monroy, Eva

In: Physica status solidi (c), 2007, vol. 4, no. 5, p. 1621-1624

We report on a prototype electro-optical modulator at telecommunication wavelength based on intersubband (ISB) transitions in a short-period GaN/AlN superlattice (SL). The device has a vertical architecture resembling a nitride-based high-electron mobility transistor, whose barrier layer has been replaced by a 5 period SL. By applying an electrical field, we were able to influence the...

Université de Neuchâtel

III-Nitride Nanostructures for Infrared Optoelectronics

Monroy, Eva ; Guillot, Fabien ; Leconte, Sylvain ; Bellet-Amalric, Edith ; Nevou, Laurent ; Doyennette, Laeticia ; Tchernycheva, Maria ; Julien, François H. ; Baumann, Esther ; Giorgetta, Fabrizio R. ; Hofstetter, Daniel ; Dang, Le Si

In: Acta Physica Polonica A (Proceedings of the XXXV International School of Semiconducting Compounds), 2006, vol. 110, no. 3, p. 295-301

Thanks to their large conduction band offset (~1.8 eV for the GaN/AlN system) and subpicosecond intersubband scattering rates, III-nitride heterostructures in the form of quantum wells or quantum dots are excellent candidates for high-speed unipolar devices operating at optical-fiber telecommunication wavelengths, and relying on the quantum confinement of electrons. In this work, we present the...

Université de Neuchâtel

Optically nonlinear effects in intersubband transitions of GaN/AlN-based superlattice structures

Hofstetter, Daniel ; Baumann, Esther ; Giorgetta, Fabrizio R. ; Guillot, Fabien ; Leconte, Sylvain ; Monroy, Eva

In: Applied Physics Letters, 2007, vol. 91, no. 131115, p. 1-3

We report optically nonlinear processes related to near-infrared intersubband transitions in short period GaN/AlN superlattices. The strong piezo- and pyroelectric effects in this material lead to intrinsic asymmetries in the electronic potential of the superlattice, and thus to strong nonlinearities of the optical susceptibility. Because of the large intersubband transition energy of nearly 1 eV...

Université de Neuchâtel

Electrically adjustable intersubband absorption of a GaN/AlN superlattice grown on a transistorlike structure

Baumann, Esther ; Giorgetta, Fabrizio R. ; Hofstetter, Daniel ; Leconte, Sylvain ; Guillot, Fabien ; Bellet-Amalric, Edith ; Monroy, Eva

In: Applied Physics Letters, 2006, vol. 89, no. 101121, p. 1-3

The authors report on electromodulated intersubband (ISB) absorption experiments on AlN/GaN superlattices (SLs) grown on a transistorlike structure. A sample containing five SL periods shows two distinct absorption peaks related to ISB transitions in the SL and in the two dimensional electron gas located at the interface of the lowest SL barrier and the underlying GaN buffer. The ratio of those...