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HL: Fachverband Halbleiterphysik

HL 70: Poster Session: Devices; Preparation and characterization; C/diamond; Si/Ge

HL 70.7: Poster

Wednesday, March 13, 2013, 16:00–20:00, Poster A

Two-photon quantum well infrared photodetectors in the THz regime — •Carsten Franke¹, Harald Schneider¹, and Martin Walther² — ¹Helmholtz-Zentrum Dresden-Rossendorf — ²Fraunhofer IAF Freiburg

Two-photon quantum well infrared photodetectors (QWIPs) are interesting nonlinear devices for autocorrelation measurements in the mid-infrared and THz-regime. Here, we present first results on two-photon THz-QWIPs with intersubband transition frequencies below 7 THz, based on the GaAs/AlGaAs material system with an aluminium content of 5% and below. We performed dark current measurements and observed large current discontinuities which can be attributed to impact ionisation. We also present photocurrent spectra which show, in addition to the expected intersubband transitions, evidence of further signatures related to optical-phonons.