Université de Neuchâtel

GaN/AlN short-period superlattices for intersubband optoelectronics: A systematic study of their epitaxial growth, design, and performance

Kandaswamy, Prem K. ; Guillot, Fabien ; Bellet-Amalric, Edith ; Monroy, Eva ; Nevou, Laurent ; Tchernycheva, Maria ; Michon, A. ; Julien, François H. ; Baumann, Esther ; Giorgetta, Fabrizio R. ; Hofstetter, Daniel ; Remmele, T. ; Albrecht, M. ; Birner, S. ; Dang, Le Si

In: Journal of Applied Physics, 2008, vol. 104, no. 9, p. 093501 1-8

We have studied the effect of growth and design parameters on the performance of Si-doped GaN/AlN multiquantum-well (MQW) structures for intersubband optoelectronics in the near infrared. The samples under study display infrared absorption in the 1.3–1.9 μm wavelength range, originating from the photoexcitation of electrons from the first to the second electronic level in the QWs. A...

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has a vertical architecture resembling a nitride-based high-electron mobility transistor, whose barrier layer has been replaced by a 5 period SL.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

High-quality AlN/GaN-superlattice structures for the fabrication of narrow-band 1.4 µm photovoltaic intersubband detectors

Hofstetter, Daniel ; Baumann, Esther ; Giorgetta, Fabrizio R. ; Graf, Marcel ; Maier, Manfred ; Guillot, Fabien ; Bellet-Amalric, Edith ; Monroy, Eva

In: Applied Physics Letters, 2006, vol. 88, no. 121112, p. 1-3

We report on high-quality short-period superlattices in the AlN/GaN material system. Thanks to significant advances in the epitaxial growth, up to 40 superlattice periods with a total layer thickness of 120 nm could be grown without cracking problems. Given an intersubband transition energy on the order of 910 meV, these superlattices could be used as room temperature, narrow-band, photovoltaic...

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...