(Color online) Schematic diagram showing different light scattering processes. (a) Elastic Rayleigh process. (b) Inelastic Stokes and anti-Stokes Raman process. (c) Phonon-assisted photoluminescence processes. Outgoing (left) and incoming (right) resonant cases.
(Color online) Photoluminescence spectra at 2 K of InAs QDs for different resonant excitation energies of (a) 1.158 eV, (b) 1.136 eV, (c) 1.089 eV, and (d) 1.051 eV. The arrows display the energy separation of the first (1LO) and second (2LO) order optical phonons. The dashed lines account for the non-resonant excitation case (E exc = 1.6 eV).
(Color online) Energy position of the maximum intensity of the transitions of Fig. 2 as a function of the excitation energy. In the inset, a photoluminescence excitation spectrum (PLE) with the detection energy set to the GS position.
(Color online) Photoluminescence spectra for resonant excitation (E exc = 1.136 eV) at different temperatures. In the inset, the maximum intensity of the 1LO, 2LO, and GS are shown as a function of temperature.
(Color online) Steady-state photoluminescence spectrum for resonant excitation (E exc = 1.158 eV). The insets show the dynamical response detected at (a) the GS + 3LO energy and, (b) the LO at 34.6 meV at 2 K. The vertical arrows indicate the energy position of each transient.
(Color online) Comparison of the measured transient for the 1LO phonon transition at 34.6 meV with theoretical calculations. The laser excitation was set to 1.136 eV and the temperature to 75 K. The red dots represent the experimental data, while the solid blue line accounts for the calculated incoherent (τd 1) and coherent (τd 2) components.
(Color online) Intensity of the LO (black quadrangles) and 2LO (red circles) signals for varying excitation energies. In addition, the fraction of the LO signal assigned to the Raman scattering has been estimated and is shown by the blue line with triangles.
(Color online) Decay dynamics of the LO mode for 1.136 eV laser excitation and for different temperatures of 5, 75, and 200 K.
Lifetimes and intensities of the decay components of the 1LO mode around 34.4 meV as a function of the excitation energy.
Temperature-dependent time-resolved photoluminescence of the LO mode at 34.6 meV for 1.136 eV of laser excitation. τ d 1: long component (incoherent), τd 2: short component (coherent). Intensity ratio between 1 and 2. τr : rise time.
Article metrics loading...
Full text loading...