Abstract-Terahertz absorbing AlGaN/GaN multi-quantum-wells: Demonstration of a robust 4-layer design

M. Beeler¹, C. Bougerol², E. Bellet-Amalric¹, and E. Monroy¹

¹CEA-CNRS Group “Nanophysique et semiconducteurs,” INAC-SP2M, CEA-Grenoble, 17 rue des Martyrs, 38054 Grenoble Cedex 9, France
²CEA-CNRS Group “Nanophysique et Semiconducteurs,” Institut Néel-CNRS, 25 rue des Martyrs, 38042 Grenoble Cedex 9, France

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http://apl.aip.org/resource/1/applab/v103/i9/p091108_s1?isAuthorized=no
We report on AlGaN/GaN multi-quantum-well structures displaying intersubband absorption in the THz spectral range. First, we theoretically analyze the weaknesses of the state-of-the-art GaN-based step-quantum-well architecture from an optoelectronic standpoint. We then propose a modified geometry with improved structural robustness considering the uncertainties associated to the growth. This later structure, consisting of 4-layer quantum wells, has been grown by plasma-assisted molecular-beam epitaxy and characterized structurally and optically. Low temperature absorption of samples with different Si doping levels confirms intersubband transitions in the far-infrared, centred at 28 μm.