Regensburg 2016 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 53: Poster II
HL 53.23: Poster
Mittwoch, 9. März 2016, 09:30–13:30, Poster A
Polarization dependent coherent photocurrent spectroscopy of single InAs quantum dots at 1500 nm — •Simon Gordon1, Matusala Yacob2, Yves Alexander Leier1, Mohamed Benyoucef2, Johann Peter Reithmaier2, and Artur Zrenner1 — 1CeOPP, Universität Paderborn, Paderborn, Germany — 2INA, Universität Kassel, Kassel, Germany
For long distance quantum communication it is essential to use flying qubits in the telecom wavelength bands. Quantum emitters or detectors in this wavelength regime can be realized with InAs quantum dots (QDs) on InP substrate. In this work, such InAs QDs are investigated by low-temperature photocurrent spectroscopy. Suitable p-i-n diode structures with self-assembled QDs have been grown by molecular beam epitaxy on InP(100) substrates. The layer sequence of the diodes consists of an n-InP back contact, an intrinsic region of lattice-matched InAlGaAs, which contains the QDs -- elongated in [0-11] direction --, and a p-InP front contact. The QDs are coherently excited by an optical parametric oscillator. By changing the applied reverse voltage the resonance energy of the QD is tuned by the quantum confined Stark effect to the energy of the light pulse. By increasing the power of the excitation light pulses, we observe a clear signature of Rabi oscillations in the photocurrent. To investigate the fine structure splitting of the exciton, we also performed polarization dependent photocurrent measurements, which reveal a polarization alignment along the [0-11] and the [011] crystal axis. We are further able to estimate the Rabi frequencies of the two ground state transitions.