Regensburg 2007 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 42: GaN: devices

HL 42.5: Talk

Thursday, March 29, 2007, 15:00–15:15, H13

Optical Chemical Sensors Based on GaN/AlN Quantum Dots — •Olaf Weidemann¹, Eva Monroy², Gunther Jegert¹, Stafan Birner¹, Martin Stutzmann¹, and Martin Eickhoff¹ — ¹Walter Schottky Institut, TU München, 85748 Garching — ²DRFMC/SP2M/PSC, CEA-Grenoble, 38054 Grenoble, France

Quantum dots (QDs) are of special interest for both fundamental physics and optoelectronic applications. Controlled growth of ensembles of self-assembled GaN/AlN QDs showing efficient room-temperature luminescence has been demonstrated recently. On the other hand, GaN-based devices have been shown useful to detect chemically induced changes of the surface potential, thereby acting as chemical sensors in liquid or gaseous environments. We demonstrate the applicability of GaN QDs as optical chemical sensors, benefiting from the optical transparency of both the sapphire substrate and the AlN matrix. GaN/AlN QDs have been grown on conductive Si-doped AlGaN backcontact layers and were equipped with catalytic Pt front contacts. The optical response of such a system in terms of a change in luminescence characteristics upon exposure to hydrogen-containing gases is discussed.