III-Nitride Nanostructures for Infrared Optoelectronics
E. Monroya, F. Guillota, S. Lecontea, E. Bellet-Amalrica, L. Nevoub, L. Doyennetteb, M. Tchernychevab, F.H. Julienb, E. Baumannc, F. Giorgettac, D. Hofstetterc and Le Si Dangd
aCEA-Grenoble, DRFMC/SP2M/PSC, 17 rue des Martyrs, 38054 Grenoble, France
bInstitut d'Electronique Fondamentale, Université Paris-Sud, 91405 Orsay, France
cUniversity of Neuchâtel, 2000 Neuchâtel, Switzerland
dLaboratoire de Spectrométrie Physique, Université Joseph Fourier, 38402 Saint Martin d'Hères, France
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Received: 17 06 2006;
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 plasma-assisted molecular-beam epitaxial growth of quantum well infrared photodetector structures. The growth of Si-doped GaN/AlN multiple quantum well structures is optimized by controlling substrate temperature, metal excess and growth interruptions. Structural characterization confirms a reduction of the interface roughness to the monolayer scale. P-polarized intersubband absorption peaks covering the 1.33-1.91 μm wavelength range are measured on samples with quantum well thickness varying from 1 to 2.5 nm. Complete intersubband photodetectors have been grown on conductive AlGaN claddings, the Al mole fraction of the cladding matching the average Al content of the active region. Photovoltage measurements reveal a narrow (ȣ90 meV) detection peak at 1.39 μm at room temperature.
DOI: 10.12693/APhysPolA.110.295
PACS numbers: 73.21.Fg, 78.67.De, 85.60.Gz, 85.35.Be, 81.15.Hi, 81.07.St