Temperature-dependent carrier tunneling for self-assembled InAs/GaAs quantum dots with a GaAsN quantum well injector

Abstract

We have investigated the carrier tunneling process in a quantum-dot (QD) tunnel injection structure, which employs a GaAs1−xNx quantum well (QW) as a carrier injector. The influence of the barrier thickness between the GaAs1−xNx well and InAs dot layer has been studied by temperature-dependent photoluminescence. Although the 2.5 nm barrier sample exhibits the best tunneling efficiency, a 3.0 nm thickness for the barrier is optimum to retain good optical properties. The carrier capture time from the GaAs1−xNx QW to QD ground states has been evaluated by time-resolved photoluminescence. The result indicates that efficient carrier tunneling occurs at temperatures above 150 K due to the temperature dependent nature of phonon-assisted processes.

Impact of gain compression factor on modulation characteristics of InGaAs/GaAs self-assembled quantum dot lasers

“…Ultralow threshold current and high temperature stability has been demonstrated for 1.3 lm selfassembled quantum dot (QD) lasers by many research groups [4][5][6][7]. It is also proved that QD lasers would have a large modulation bandwidth due to the high differential gain of three dimensional confined QD states [8].…”

Ultrafast response of tunnel injected quantum dot based semiconductor optical amplifiers in the 1300 nm range

“…12 Recently, dilute nitride based injector levels have been investigated as an alternative to InGaAs layers to overcome issues of excessive strain and tunability, and efficient electron tunnelling was realised. 7,13 However, improved modulation performance has not yet been demonstrated. In order to address this point, we present an experimental analysis of the ultrafast gain and refractive index dynamics in a semiconductor optical amplifier structure.…”

“…6 However, at the technologically important 1.3 lm wavelength, good modulation performance has been difficult to realise due to the significant amount of "hot carriers" present in the system. 7 Tunnel injection (TI) structures were proposed to overcome this limitation 8 and have demonstrated modulation bandwidths in excess of 11 GHz in the 1.3 lm range 9 under quasi-cw conditions. TI based devices have also been investigated in the 1060 nm range for high power applications, 10 in spin polarised lasers, 11 and with quantum dash structures for operation in the 1550 nm range.…”

Power-dependent spin amplification in (In, Ga)As/GaAs quantum well via Pauli blocking by tunnel-coupled quantum dot ensembles

“…One example is quantum well (QW) and quantum dot (QD) tunnel-coupled nanostructures. [1][2][3][4][5][6][7][8][9] In such hybrid systems, QWs serve as reservoirs for carriers/excitons, whereas the three-dimensional (3D) potential surrounding QDs efficiently confines the carrier/exciton motion. This confinement leads to long-lived spin states due to the suppression of spin-orbit interaction-induced relaxation processes.…”