Optical properties of 1.3 μm room temperature emitting InAs quantum dots covered by In0.4Ga0.6As/GaAs hetero-capping layer

Optical investigation of InGaAs-capped InAs quantum dots: Impact of the strain-driven phase separation and dependence upon post-growth thermal treatment

“…(2), activation energy of 85 meV is obtained for E 1 and 450 MeV for E 2 . E 1 is close in magnitude to the energy spacing between successive PL excitation peaks [7]. This indicates that, for the intermediate temperature range, the carrier's thermionic emission out of the QDs takes place through upper states before escaping to the QW or the GaAs barrier.…”

“…The spectrum contains three luminescence bands denoted by E 0 , E 1 and E 2 . Previous investigation of this structure has shown that E 0 and E 1 arise from the ground state and the corresponding first excited-state emission energies, and E 2 is associated with the PL of the quantum well-like formed by the InGaAs overgrowth layer [7]. A careful attention to the evolution of the PL spectra as a function of temperature reveals an abnormal behavior.…”

“…This method is mainly based on both strain-reducing and strain-driven phase separation of the heterocapping alloy. The latter, while enhances the QD's size and throws the diffusion of In atoms to the QDs, has been recently suspected to be in the origin of the formation of potential barriers in the vicinity of the QDs [7,8], resulting in an unusual increase of the integrated photoluminescence (PL) intensity with temperature. The rapid thermal annealing (RTA) process on QDs has been commonly used to tune the electronic states and the emission wavelength, by thermal induced In/Ga intermixing.…”

Dynamics of exciton recombination in InAs quantum dots embedded in InGaAs/GaAs quantum well

“…[4] was reduced to ∼ 0.4 ns. Most recently [5], although the potential barriers were greatly reduced due to the introduction of a strain-reducing layer, the decay time was not yet measured. This work has been supported by DARPA and AFOSR.…”

Interdot spacing dependence of electronic structure and properties of multistacked InGaAs quantum dots fabricated without strain compensation technique

“…The activation energy Because multistacked QDs with a large interdot spacing exhibit no electronic coupling between QDs, the carriers in QDs are strongly quantum confined in QDs, and the activation energy increases. 14,22) For the multistacked QDs with medium interdot spacings, the wave function of electrons can be delocalized, and a miniband is formed in the QDs. However, the wave function of a hole is localized in QDs.…”