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HL: Fachverband Halbleiterphysik

HL 66: GaN: Preparation and characterization of rods and wires

HL 66.8: Vortrag

Mittwoch, 13. März 2013, 18:45–19:00, H15

Superradiant luminescence of GaN nanowires on diamond — •Fabian Schuster, Andrea Winnerl, Saskia Weiszer, Jose Garrido, and Martin Stutzmann — Walter Schottky Institut, Technische Universität München, 85748 Garching

GaN nanowires have attracted much interest in recent years due to their high crystalline quality and large surface area, desirable with respect to optoelectronics, (photo-) catalysis or sensing applications. However, these devices suffer from inefficient p-type doping, especially for AlxGa1-xN ternary alloys. In contrast, diamond with its indirect bandgap of 5.48 eV can be efficiently p-type doped, thus representing a perfect complement to the nitride material system as transparent electrode and efficient heat sink. We have recently demonstrated the growth of self-assembled GaN nanowires on (111) single-crystalline diamond substrates.[1]

In order to investigate waveguiding behaviour of the nanowires, the tips of the GaN nanowires were capped by 10 nm of AlGaN with 40% aluminum content. These capped nanowires exhibit strong superradiant photoluminescence for increasing excitation density at room temperature with a low gain threshold of 50 kW/cm2. A small variation of the emission energy with increasing excitation power indicates efficient heat dissipation by the diamond substrate.

[1] F. Schuster et al., Nano Letters 12, 2199 (2012)