Berlin 2018 – scientific programme
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DS: Fachverband Dünne Schichten
DS 17: Poster Session I
DS 17.5: Poster
Tuesday, March 13, 2018, 18:15–20:15, Poster B
Acoustic transport of charge carriers and electron spins in quantum wires — •Paul L. J. Helgers1,2, Klaus Biermann1, Haruki Sanada2, Yoji Kunihashi2, and Paulo V. Santos1 — 1Paul-Drude-Institut für Festkörperelektronik Berlin, Germany — 2NTT Basic Research Laboratories, NTT Corporation, Atsugi, Japan
We investigate a concept for acoustically driven single-photon-sources (SPS), based on planar GaAs quantum wires (QWRs) embedded in an optical microcavity. The QWRs are fabricated by photolithography, wet chemical etching and anisotropic MBE overgrowth. In this concept, spin-polarized carriers are optically injected at one end of the quantum wire and then acoustically transported to a QD-like recombination center at the other QWR end where they recombine, emitting single photons. The one-dimensionality of the QWR reduces Dyakonov-Perel spin dephasing during acoustic transport, thereby correlating the excitation polarization with the emission polarization. The SPS properties are improved by a microcavity.
In this contribution, we observe line-edge-roughness (LER), leading to QWR width variations up to several tens of nm, which complicate acoustic transport. We show that LER is mainly caused by the photolithography process. Secondly, we observe charge transport in GaAs(113)A QWRs and in cavity-embedded GaAs(001) QWRs on lengths of several tens of microns. Furthermore, spin lifetimes in the GaAs(001) QWRs approach the nanosecond timescale, promising spin transport lengths of several microns. We will evaluate the potential of these structures to be used as efficient acoustically driven SPSs.