InAs/GaAs quantum dots optically active at 1.5 μm

Abstract

InAs quantum dots grown by molecular-beam epitaxy on GaAs substrates are demonstrated to be suitable structures to achieve an optical emission in the 1.3–1.5-μm range. Their tuning towards such long wavelengths was made possible by combining an extreme reduction of the InAs growth rate and a fast growth of the GaAs cap layer at low temperature. Our results create perspectives for the fabrication of GaAs-based devices operating in the most important telecommunications window.

Formation of columnar (In,Ga)As quantum dots on GaAs(100)

“…These include QD stacking, reduction of the growth rate, and interrupted growth to control the effective QD size and shape; and the overgrowth by strain reducing ͑In,Ga͒As and ͑In,Al͒As layers. [4][5][6][7][8] We have recently introduced leveling and rebuilding of InAs QDs on GaAs͑100͒ substrates during molecular beam epitaxy (MBE) of multiple ultrathin GaAs/ InAs overlayers which drastically improves the QD size uniformity and optical properties due to the exchange of InAs between neighboring QDs. 9 Here we report leveling and rebuilding as an effective route for the creation of height controlled columnar ͑In,Ga͒As QDs.…”

Room-temperature 1.6μm light emission from InAs∕GaAs quantum dots with a thin GaAsSb cap layer

“…1 High-performance InAs/ GaAs QD lasers, with emission close to 1.3 m, have been demonstrated using InGaAs, InAl͑Ga͒As, and GaAsSb capping layers ͑CLs͒ to directly cover the InAs QDs. [2][3][4][5][6] In addition, there have been a number of attempts to extend the emission wavelength beyond 1.5 m, with room-temperature ͑RT͒ photoluminescence ͑PL͒ above 1.5 m having been demonstrated for large InAs/ GaAs QDs, 7 GaInNAs/ GaAs QDs, 8 InAs QDs with an In 0.45 Ga 0.55 As CL, 9 InAs QDs with InGaNAs CL, 10 and InAs QDs grown on InGaAs or GaAsSb metamorphic buffer layers. 11,12 In a previous letter, we reported ϳ1.3 m emission from InAs QDs with a GaAsSb CL.…”

Radiative Recombination Mechanisms of Large InAs/GaAs Quantum Dots

“…Systems based on large-size InAs/GaAs QDs, obtained by low growth rates, have been shown to be optically active in the vicinity of 1.3 and 1.5 µm [11,13]. Although this technique usually leads to lower QD densities (1010 cm -2 ), its advantage is that the confinement energy in the nanostructures is larger than in usual QDs (obtained with higher growth rates) and yields a better temperature stability of the devices.…”

“…However, an important issue still remains: the achievement of a reliable and cheap semiconductor laser operating in the telecommunication windows at 1.3 or 1.55 µm corresponding, respectively, to the minimum dispersion and attenuation of the optical signal in silicate optical fibers [11,12]. Systems based on large-size InAs/GaAs QDs, obtained by low growth rates, have been shown to be optically active in the vicinity of 1.3 and 1.5 µm [11,13].…”