Random Population of Quantum Dots in InAs–GaAs Laser Structures

O'Driscoll, I.; Blood, P.; Smowton, Peter M.

doi:10.1109/jqe.2009.2039198

Cited by 34 publications

(22 citation statements)

References 21 publications

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“…QD-based lasers were predicted to have low, temperature-insensitive threshold currents [2,3] but this requires large energy separations between the discrete QD states to suppress thermal effects. At low temperatures QD devices do indeed exhibit close to ideal characteristics, but by room temperature their performance is consistent with thermal spreading across available energy states with critical temperature values not significantly better than quantum well lasers [4][5][6]. In this paper we show that using electrical measurements of the diode behavior of QD lasers operating well below the lasing threshold, we can obtain valuable additional information on the transfer of carriers across the diode across a wide temperature range.…”

Section: Introductionmentioning

confidence: 56%

Subthreshold diode characteristics of InAs/GaAs quantum dot lasers

et al. 2011

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The temperature dependence of the carrier dynamics in ensembles of InAs/GaAs quantum dots (QDs) are of interest, both from a fundamental point of view but also because of the consequences for the performance of QD-based optoelectronic devices.While this topic has been studied before using optical techniques, here we approach the topic by analyzing the current-voltage (IV) characteristic of QD diodes. Using a current-modulation technique, the transition from "trap-like" to "thermalized" behavior as the temperature is raised from 80 K to room-temperature is observed.Furthermore, the results suggest that the IV curve is sensitive to the separate escape of electrons and holes and the intersubband spacing of the electron states and that of the hole states is estimated from the data.2

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Section: Introductionmentioning

confidence: 56%

Subthreshold diode characteristics of InAs/GaAs quantum dot lasers

et al. 2011

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“…3 was obtained as follows. The PL for the dots is (n d /s rad ) (with s rad ¼ 1 ns obtained from the measured absorption cross section 9 ) and was calculated by making sensible adjustment to C w and C d to match the experimental data in Fig. 3, and changing G proportional to the incident power for each of the curves.…”

Section: Effect Of Proton Bombardment On Inas Dots and Wetting Layer mentioning

confidence: 99%

Effect of proton bombardment on InAs dots and wetting layer in laser structures

O'Driscoll

Blood

Smowton

et al. 2012

Applied Physics Letters

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The effect of proton bombardment on carrier lifetime and photoluminescence of InAs quantum dots was measured. Optical absorption and transmission electron microscopy show the dots retain their integrity under bombardment. A decrease in ground state photoluminescence with increasing dose is not explained by the decrease in dot carrier lifetime alone, but also by bombardment-induced non-radiative recombination in the wetting layer, which reduces the dot electron population at fixed excitation. To exploit the relative radiation immunity of quantum dots, it is necessary to maximise the dot density and capture probability per dot to minimize the effect of wetting layer recombination.

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“…4 This has a profound influence on the temperature dependence of threshold current. 5 It has recently been demonstrated that random occupation in QD systems can improve mode locked laser performance where pulse widths as short as 290 fs were observed from a QD sample at 20 K, believed to be operating in the random regime. 6 The evidence for random occupancy on the dots was provided by fitting model calculations to the radiative threshold current of the laser.…”

mentioning

confidence: 99%