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Université de Neuchâtel

Mid-infrared quantum cascade detectors for applications in spectroscopy and pyrometry

Hofstetter, Daniel ; Giorgetta, Fabrizio R. ; Baumann, Esther ; Yang, Quankui ; Manz, Christian ; Köhler, Klaus

In: Applied Physics B : Lasers and Optics, 2010, vol. 100, no. 2, p. 313-320

In this paper, we give an overview of quantum cascade detector technology for the near- and mid-infrared wavelength range. Thanks to their photovoltaic operating principle, the most advanced quantum cascade detectors offer great opportunities in terms of high detection speed, reliable room temperature operation, and excellent Johnson noise limited detectivity. Besides some important features...

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

Quantum Cascade Detectors

Giorgetta, Fabrizio R. ; Baumann, Esther ; Graf, Marcel ; Yang, Quankui ; Manz, Christian ; Köhler, Klaus ; Beere, Harvey E. ; Ritchie, David A. ; Linfield, Edmund ; Davies, Alexander G. ; Fedoryshyn, Yuriy ; Jackel, Heinz ; Fischer, Milan ; Faist, Jérôme ; Hofstetter, Daniel

In: IEEE Journal of Quantum Electronics, 2009, vol. 45, no. 8, p. 1039-1052

This paper gives an overview on the design, fabrication, and characterization of quantum cascade detectors. They are tailorable infrared photodetectors based on intersubband transitions in semiconductor quantum wells that do not require an external bias voltage due to their asymmetric conduction band profile. They thus profit from favorable noise behavior, reduced thermal load, and simpler...

Université de Neuchâtel

Intersubband Transition-Based Processes and Devices in AlN/GaN-Based Heterostructures

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. ; Guillot, Fabien ; Monroy, Eva

In: Proceedings of the IEEE, 2010, vol. 98, no. 7, p. 1234-1248

We report on the physics, epitaxial growth, fabrication, and characterization of optoelectronic devices based on intersubband transitions in the AlN/GaN material system. While in 1999, only results of optical absorption experiments could be shown, photodetectors and modulators with operation frequencies beyond 10 GHz as well as optically pumped light emitters have been demonstrated recently. This...

Université de Neuchâtel

Performance improvement of AlN/GaN-based intersubband detectors thanks to quantum dot active regions

Hofstetter, Daniel ; Di Francesco, Joab F. ; Baumann, Esther ; Giorgetta, Fabrizio R. ; Kandaswamy, Prem K. ; Das, Aparna ; Valdueza-Felip, Sirona ; Monroy, Eva

In: IR Focal Plane and Detector Development II (Proceedings of SPIE), 2010, vol. 7808, no. 78080A, p. 1-8

Since the operating mode of 1.55 µm AlN/GaN-based intersubband photodetectors is based on optical rectification, both the excited state lifetime and the lateral displacement of the carriers play an important role for performance optimization. We thus show here results of an improved detector generation based on a novel type of active region. Thanks to the use of quantum dots instead of quantum...

Université de Neuchâtel

Midinfrared quantum cascade detector with a spectrally broad response

Hofstetter, Daniel ; Giorgetta, Fabrizio R. ; Baumann, Esther ; Yang, Quankui ; Manz, Christian ; Köhler, Klaus

In: Journal of Applied Physics, 2008, vol. 93, no. 22, p. 221106 1-3

A midinfrared quantum cascade detector with a spectrally broad (ΔE/E = 27.3%) response is designed, fabricated, and tested. This detector consists of 26 differently designed active region stages in order to cover a wavelength region from 4.7 to 7.4 μm. The device could be operated above room temperature and showed peak responsivities of 13 mA/W at 10 K and 1.25 mA/W at...

Université de Neuchâtel

High frequency measurements on an AlN/GaN-based intersubband detector at 1550 and 780 nm

Hofstetter, Daniel ; Baumann, Esther ; Giorgetta, Fabrizio R. ; Dawlaty, Jahan ; George, Paul A. ; Rana, Farhan ; Guillot, Fabien ; Monroy, Eva

In: Journal of Applied Physics, 2008, vol. 92, p. 231104 1-3

We report on high frequency measurements on an AlN/GaN-based intersubband detector using mode-locked solid state lasers. Our experiments involving laser wavelengths of 1550 and 780 nm demonstrate not only the capability of such devices to work both at the fundamental and at a higher order intersubband transition, but they also allowed us to push the high frequency detection limit up to a value...

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

Mid-infrared quantum cascade detectors for applications in spectroscopy and pyrometry

Hofstetter, Daniel ; Giorgetta, Fabrizio R. ; Baumann, Esther ; Yang, Quankui ; Manz, Christian ; Köhler, Klaus

In: Quantum Sensing and Nanophotonic Devices VII, 2010, vol. 7608, no. 76081N, p. 1-11

An overview of quantum cascade detector technology for the near- and mid-infrared wavelength range will be given. Thanks to photovoltaic instead of photoconductive operation, quantum cascade detectors offer great opportunities in terms of detection speed, room temperature operation, and detectivity. Besides some crucial issues dealing with fabrication and general characteristics, some...

Université de Neuchâtel

Monolithically integrated UV/IR-photodetectors based on an AlN/GaN-based superlattice grown on an AlGaN buffer layer

Hofstetter, Daniel ; Baumann, Esther ; Giorgetta, Fabrizio R. ; Théron, Ricardo ; Guillot, Fabien ; Monroy, Eva ; Golka, Sebastian ; Strasser, Gottfried

In: Physica status solidi (c), 2009, vol. 6, no. 2, p. S818-821

In this article, we demonstrate closely spaced, monolithically integrated photodetectors in two largely different wavelength ranges. The epitaxial structure of the devices was grown by plasma-assisted molecular-beam epitaxy on an AlN-on-sapphire template; it consists of a Si-doped AlGaN thin film, and a nearly strain compensated 40 period AlN/GaN superlattice with 1.0 nm thick GaN quantum wells...