Dresden 2011 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 7: Single Photon Sources and Qbits
HL 7.6: Vortrag
Montag, 14. März 2011, 12:15–12:30, FOE Anorg
SiGe-quantum dot arrays for Single Photon Detection — •Jürgen Moers1,2, Natalia P. Stepina3, Julian Gerharz1,2, Anatoly V. Dvurechenskii3, and Detlev Grützmacher1,2 — 1Institute of Bio- and Nanosystems, Forschungszentrum Jülich, D 52425 Jülich, Germany — 2Jülich Aachen Research Alliance — 3Institute of Semiconductor Physics, Russian Academy of Science, 630090 Novosibirsk, Russia
Emission and detection of single photons is required for a broad range of future device applications. In this work a Si based single photon detector employing hopping transport in densely packed Ge quantum dot (Ge-QD) arrays is proposed. The hopping transport through a high-density Ge-QDs array crucially depends on the average occupation of the Ge-QD array. Changing the charge state of one QD by illumination causes a change in the conductance of the whole array. Thus, step-like variations of the conductance due to the absorption of single photons and hence carrier generation in one single dot is noticeable. Time resolved 4-point measurements of the conductance of the device at 4.2K were performed. A fiber coupled laser with 1.55 µm wavelength and initial laser power of 1 mW was used for illumination. To get extremely low light intensity the initial laser power was attenuated up to 60 dB. The conductance traces of the device show step like changes due to single Ge-QD charging and discharging. It could be shown, that the number of these events depends linearly on the light intensity, which is a prerequisite for single photon detection.