Carrier thermodynamics inInAs∕InxGa1−xAsquantum dots

Size dependent carrier thermal escape and transfer in bimodally distributed self assembled InAs/GaAs quantum dots

“…8,9 However, the same effect was explained considering the saturation of temperature activated trap states in the barrier. 10 Lobo et al 7 found that the efficiency on carrier transfer is limited by the rate of carrier transfer on the WL only for low density samples, and normal Arrhenius dependence has been found for high density samples. A similar result by Zhou et al 19 concluded that the WL might act as a quenching (transfer) channel for low (high) density samples while Torchynska 23 has reported that the effective thermal activation energy might depend on the QD density.…”

“…[23][24][25][26] Thermal escape can be also investigated attending to the nature of the particles being promoted to a higher energy state. 14 Depending on the model, the correlated (excitonic escape), 6,8,10,12,23 the uncorrelated electron-hole pair (ambipolar escape), 4,9,14 or just one of the carriers (unipolar escape) 15 can be considered. Whether one or the other is appropriate in a particular sample depends on the barrier height and therefore might vary for QDs of given composition but different size.…”

“…A variety of carrier redistribution effects caused by temperature has been investigated in QD ensembles. [4][5][6][7][8][9][10][11][12][13][14][15] It is commonly accepted that the sigmoidal evolution of the peak energy and full width at half maximum of the PL bands is due to carrier promotion from small QDs to larger ones. 6 Therefore, quantum dot size distributions, carrier capture, relaxation, and re-trapping among QDs of different sizes had to be considered to model correctly the QD recombination dynamics.…”

Improved Optoelectronic Properties of Rapid Thermally Annealed Dilute Nitride GaInNAs Photodetectors

“…A slope of 1 on the log-log plot of IEL intensity versus injection current indicates very efficient radiative recombination, whereas a slope of 2 indicates that defect-related nonradiative recombination is dominant. 28 It can be seen in Fig. 8a that the IEL intensity of the as-grown devices in this work and the as-grown Ga 0.90 In 0.10 N 0.038 As 0.962 devices in Ref.…”

Femtosecond pulse generation in passively mode locked InAs quantum dot lasers

“…We observe that at temperatures below the minimum in threshold, the emission spectra broaden and analysis of the emission data at 20 K shows ground states in different size dots are populated with equal probability, increasing with drive current, indicative of random behaviour. 18 We have compared this data with rate equation calculations of gain spectra for inhomogeneous distributions of ground and excited states, interacting via a thermal phonon bath with each other and with the wetting layer, and in which population of dots by electrons and holes is correlated, 12,14,22 controlled by separation of the dot electron state from the wetting layer ($0.28 eV for the ground state). Measured modal absorption spectra provided input values for the gain coefficient and spontaneous recombination lifetime (via the Einstein relations), which were temperature independent, and for the wetting layer band edge energy; energies and distributions of dot transitions were determined by Gaussian fits.…”