CC BY
0MBE growth and properties of III-V quantum dots in nanowires
for single photon sources
R. Reznik1*, D. Barettin2, R. Radhakrishnan3, N. Akopian3, G. Cirlin4
1- St. Petersburg State University, Universitetskaya Embankment 7-9, 199034 St. Petersburg, Russia 2- Universita degli Studi Niccold Cusano - Telematica, via don Carlo Gnocchi 3, 00166 Rome, Italy 3- Technical University of Denmark, DK 2800 Lyngby, Denmark 4- Alferov University, Khlopina 8/3, 194021 St. Petersburg, Russia
* r.reznik@spbu.ru
A combination of nanowires (NWs) with quantum dots (QDs), are promising building blocks for future optoelectronic devices, in particular, single-photon emitters [1]. The most studied epitaxially grown QDs are self-assembled, i.e., grown by island nucleation in the Stranski-Krastanov growth mode. In common case, the size, shape, and density of self-assembled QDs can be changed by growth parameters, but it is a strain induced process and controlling the properties of the array independently is a challenging task [2]. QDs in nanowires have in contrast shown great potential as a highly controllable system. The diameter, height, and density of the QDs are defined by the NW diameter, the growth time, and the NW density, respectively, and can be chosen more predictable. Moreover, the unique morphology of NWs makes it possible to integrate such direct-gap hybrid nanostructures with a silicon platform [3].
Fig. 1. (a) Typical TEM image of single AlGaAs NW with InGaAs QD grown at 510°C. (b) Typical HRTEM image of InGaAs QD in single AlGaAs NW grown at 510°C. (c) Typical diffraction pattern obtained in QD location. (d) Schematic representation of AlGaAs NWs with InGaAs QDs structure.
In this work we present for the first time MBE growth of QDs in NWs based on (In)GaAs/AlGaAs materials system on silicon surface also studied their physical properties. The example of AlGaAs NW with InGaAs QD typical transmission electron microscopy (TEM) images, diffraction pattern and schematic representation of the structure are shown in the Fig. 1 (a-d). Studies results have shown that grown hybrid nanostructures are efficient single photons sources and by changing the size and composition of QDs we can strictly control the emission energy from the QD in a wide range. It is important to note that the direction of emission from QDs in the body of NWs was studied experimentally and theoretically. Our work opens new prospects for integration of direct band-gap semiconductors and single-photon sources on silicon platform for various applications in the fields of silicon photonics and quantum information technology.
[1] R. Singh and G. Bester, Nanowire quantum dots as an ideal source of entangled photon pairs, Physical review letters, 103, 063601, (2009).
[2] V.G. Dubrovskii, G.E. Cirlin, V.M. Ustinov, Kinetics of the initial stage of coherent island formation in heteroepitaxial systems, Physical Review B, 68, 075409, (2003).
[3] T. Mârtensson, C.P.T. Svensson, B.A. Wacaser, M.W. Larsson, W. Seifert, K. Deppert, A. Gustafsson, L.R. Wallenberg, L. Samuelson,
Epitaxial III-V nanowires on silicon, Nano letters, 4, 1987-1990, (2004).
