Dresden 2014 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 65: Quantum Dots: Optical Properties II (organized by HL)
TT 65.5: Vortrag
Mittwoch, 2. April 2014, 12:30–12:45, POT 251
Photocurrent spectroscopy of single InAs quantum dots at 1500 nm — •Simon Gordon1, Matusala Yacob2, Yves Alexander Leier1, Dirk Mantei1, 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 on InP substrate. In this work, such InAs quantum dots are investigated by low-temperature high resolution photocurrent spectroscopy. Suitable p-i-n diode structures with self-assembled quantum dots 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 quantum dots, and a p-InP front contact. The quantum dots are resonantly excited by a tunable single-frequency diode laser. By changing the applied reverse voltage the resonance energy of the quantum dot is tuned by the quantum confined Stark effect with respect to the laser line. We observe clear ground state absorption of single dots over a large tuning range in the photocurrent response. The highly resolved absorption lines show for the investigated samples no fine-structure splitting. This behavior could be caused by single electron charging, which leads to the decay of trions.