Dresden 2009 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 50: Ultra fast phenomena
HL 50.2: Talk
Friday, March 27, 2009, 10:30–10:45, BEY 118
Terahertz wave emission from an InGaAsN large area emitter — •Falk Peter1, Stephan Winnerl1, Harald Schneider1, Manfred Helm1, and Klaus Köhler2 — 1Forschungszentrum Dresden-Rossendorf — 2Fraunhofer-Institute for Applied Solid State Physics, Freiburg
We present large-area emitters [1] based on InGaAsN which show efficient THz emission for excitation wavelengths up to 1.35 μm [2]. The substrate material consists of a 1000 nm thick Ga(y)In(1-y)As(1-x)N(x) (y=0.11 and x=0.04) layer grown by molecular-beam epitaxy on semi-insulating GaAs. On top there is an additional GaAs/Al(0.3)Ga(0.7)As heterostructure with thicknesses of 5 nm for the GaAs and 60 nm for the AlGaAs layer, respectively. Transmission measurements with a Fourier spectrometer reveal a bandgap corresponding to a wavelength of 1.5 μm. The resistance of a complete device with an active area of 1 mm^2 is 0.3 MΩ. For excitation an optical parametric oscillator (OPO), tunable between 1.1 μm and 1.5 μm, is used. The THz signal is detected using electro-optical sampling with ZnTe crystal. The gating beam (λ = 820 nm) for detection is split off from a Ti:sapphire oscillator which pumps the OPO. In contrast to conventional dipole antennas no saturation was observed within the available range of average power (up to 50 mW).
[1] A. Dreyhaupt, et al., Appl. Phys. Lett. 86, 121114 (2005).
[2] F. Peter et al., Appl. Phys. Lett. 93, 101102 (2008).