InAs quantum dot in a needlelike tapered InP nanowire: a telecom band single photon source monolithically grown on silicon

Abstract

Realizing single photon sources emitting in the telecom band on silicon substrates is essential to reach complementary-metal-oxide-semiconductor (CMOS) compatible devices that secure communications over long distances. In this work, we propose the monolithic growth of needlelike tapered InAs/InP quantum dot-nanowires (QD-NWs) on silicon substrates with a small taper angle and a nanowire diameter tailored to support a single mode waveguide. Such a NW geometry is obtained by a controlled balance over axial and radial growths during the gold-catalyzed growth of the NWs by molecular beam epitaxy. This allows us to investigate the impact of the taper angle on the emission properties of a single InAs/InP QD-NW. At room temperature, a Gaussian farfield emission profile in the telecom O-band with a beam divergence angle θ = 30° is demonstrated from a single InAs QD embedded in a 2° tapered InP NW. Moreover, single photon emission is observed at cryogenic temperature for an off-resonant excitation and the best result, g 2 (0) = 0.05, is obtained for a 7° tapered NW. This all-encompassing study paves the way for the monolithic integration on silicon of an efficient single photon source in the telecom band based on InAs/InP QD-NWs.Epitaxy, Gaussian far-field emission profile, Telecom band, Silicon integration Non-classical light sources emitting at optical communication wavelength bands are of prime importance to quantum communication applications. One of these sources is the single photon source (SPS) which is the building block for realizing scalable on-chip devices for quantum 3 information processing. Once the single photons are generated, it is then required to manipulate the photons either to encode the information or to make the measurements. This means that the SPS must be integrated with compact photonic devices that can combine many optical components. Thanks to its large refractive index, silicon (Si) facilitates the fitting of a high number of optical components into a small device size making it a powerful platform for photonic integrated circuits. 1 Moreover, Si appears to be the most compatible material, due to the maturity of the complementary-metal-oxide-semiconductor (CMOS) fabrication methods, to combine electronics with photonics. 2 However, Si is an indirect band gap material which makes it a very poor light source. This issue can be solved by the monolithic integration, bonding or pick-andplace procedure of III-V materials on Si to fabricate CMOS compatible SPS. [3][4][5][6] In addition to the substrate choice, SPS emitting in the 1.3 µm and 1.5 µm telecom windows are required to reduce the losses for fiber-based long-haul communications. In particular, InAs quantum dots (QDs) have proven to be good candidates as efficient non classical light sources in these bands. 7,8 This requires embedding the QD in a nanophotonic structure such as nanowires (NWs), 9 micropillars, 10 optical horns, 11 photonic crystal cavities 12,13 and waveguides 14 in order to guide and efficiently extract the light in free space...

Purcell Effect and Beaming of Emission in Hybrid AlGaAs Nanowires with GaAs Quantum Dots

“…An important property of NW is its possibility to control spontaneous emission rates, providing an inhibition as well as an enhancement of spontaneous emissions (SE) [6][7][8]. Tunneling of the spontaneous emissions of QD in NW into a single photonic mode is a critically important task for the realization of practical devices and many efforts have been made to provide directional emission of radiation from NW with QD [9][10][11]. The common approach is based on an emission of QD into the fundamental waveguide mode HE 11 , and a subsequent beaming of radiation via tapering of the shape of NW [12,13].…”

“…A concentration of the attention on the HE 11 mode (possessing non-zero radial component of the electric field near axis of the NW) is justified by the fact in GaAs quantum wells, and an electric dipole moment of the exciton ground state is oriented along the interface of quantum wells in the radial direction [7,10,[14][15][16].…”

Highly linear polarized emission at telecom bands in InAs/InP quantum dot-nanowires by geometry tailoring

“…Integrating III-V semiconductor nanowires (NWs) on silicon substrates has been widely studied to achieve telecom band NW lasers 1 and single photon sources 2 , light emitting diodes 3 , photovoltaics cells 4 or photodetectors. 5 Tailoring the NW shape is a key issue to optimize the device efficiency.…”

Направленное излучение из квантовых точек GaAs в теле нитевидных нанокристаллов AlGaAs

“…Для наиболее полного использования подобных наноструктур в оптоэлектронных приложениях исследование направленности излучения из КТ в теле ННК является критически важным [12]. Ранее для системы материалов InP/InAs 1−x P x было показано, что ННК могут обладать волноводными свойствами для излучения из КТ, причем изменение отношения диаметра ННК к длине волны излучения из КТ приводит к изменению интенсивности излучения [13,14].…”