Many-body formulation of carriers capture time in quantum dots applicable in device simulation codes

Vallone, Marco

doi:10.1063/1.3309838

Cited by 5 publications

(1 citation statement)

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“…Gomis-Bresco et al 6 explained this behaviour with the occurrence of extremely efficient direct capture processes from two dimensional QW states into the QD GSs and ESs, governed by characteristics time constants much smaller than the characteristic relaxation time from ES 1 to GS. Such a behaviour however is not consistent with capture time calculations provided by Nielsen 2 and Vallone 7 where direct capture processes were found to only weakly contribute to the overall carrier dynamics due to the large energy difference between initial and final states.…”

Section: Introductioncontrasting

confidence: 50%

Modeling differential transmission spectroscopy experiments in quantum dot optical amplifiers and saturable absorbers

2010

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We present a numerical model based on a time-domain travelling-wave approach to describe pulse propagation in InAs Quantum-Dot (QD) based Semiconductor Optical Amplifiers (SOA) and Saturable Absorbers (SA). The onedimensional field propagation equation is solved in the time domain, in the slowly varying envelope approximation and it is coupled to a set of multi-population rate-equations modeling carrier dynamics in the QD layers in each longitudinal section of the waveguide. The optical response of the QD active medium is introduced in the field equation via a proper polarization term described as a set of infinite impulse response numerical filters. The inhomogeneous broadening of the density of states of the QD system induced by the QD size dispersion is properly taken into account. The influence of a static electric field on carrier dynamics in a reversely biased SA is described in the rate equations via bias dependent thermionic escape rates and tunneling processes. Absorption dynamics in a QD SA shows an initial ultrafast, bias independent recovery, followed by a slower recovery strongly dependent on the applied reverse bias. The QD SOA shows instead a dominant ultrafast gain recovery on a subpicosecond time scale at both QD Ground-States (GS) and first Excited-States (ES 1 ) wavelengths. Direct capture/escape processes between quantum well states and deeply confined QD states slightly influence the gain and absorption dynamics.

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Section: Introductioncontrasting

confidence: 50%