Papers by Reinaldo Ferreira
Semiconductor Science and Technology, 1990
The authors report theoretical results pertaining to the electronic properties of Ga(In)As-based ... more The authors report theoretical results pertaining to the electronic properties of Ga(In)As-based quantum wells and superlattices. The focus is on a comparison between the Ga0.47In0.53As-InP and Ga0.47In0.53As-Al0.48In0.52As systems where the well-acting material is the same, the barrier-acting materials are very similar but where the conduction band offsets are very different ( approximately=0.24 and 0.44 eV respectively). Features of electron and hole energy levels as well as scattering lifetimes are discussed.
Semiconductor Science and Technology, 2004
We present a model which treats non-perturbatively the effects of both dipolar coupling and reser... more We present a model which treats non-perturbatively the effects of both dipolar coupling and reservoir fluctuations on the interband optical response of a single quantum dot. We are able to study the transition to a Rabi-like situation with increasing excitation power. The incorporation of an energy relaxation process (for instance, due to polaron relaxation among the dot polaron levels) in a three-level system allows us to simulate both photoluminescence (PL) and photoluminescence excitation experiments. The PL spectrum displays one or a few lines depending on the excitation intensity, relaxation efficiency and reservoir fluctuation rates.
Semiconductor Science and Technology, 2004
ABSTRACT We discuss the role of excitonic polarons on the interband optical properties of single ... more ABSTRACT We discuss the role of excitonic polarons on the interband optical properties of single self-assembled semiconductor quantum dots. We show in particular that the strong coupling to optical phonons leads to fundamental modifications in the description of the excitation, relaxation and luminescence processes, as compared to previous schemes, and that the use of excitonic polaron states provides a coherent model for the description of various interband optical processes.
Experimental Thermal and Fluid Science, 1989
1An analysis of the incompressible, laminar, and isothermal flow in radial diffusers is reported.... more 1An analysis of the incompressible, laminar, and isothermal flow in radial diffusers is reported. The work was motivated by the importance of this type of flow in evaluating the performance of the valve systems of reciprocating hermetic compressors. Due to the small distance between disks, the experiment is very difficult to perform, and special attention was devoted to the control of the geometric parameters of the model. This work emphasizes the importance of comparing numerical and experimental results for the validation of both numerical model and experimental setup. Pressure distributions along the flow and the resultant axial force acting on the reed are presented for various flow Reynolds numbers and axial gaps. A complete description of the experimental setup is also included.
Experimental Thermal and Fluid Science, 1993
Research was carried out on the heat transfer due to a submerged slot jet of water impinging on a... more Research was carried out on the heat transfer due to a submerged slot jet of water impinging on a circular cylinder in cross-flow. The cylinder diameter and the slot width are of the same order of magnitude, specifically D s = 2.0 and 3.0 mm and D c = 2.5 and 3.0 mm. The experimental apparatus allowed the variation of the slot width, the cylinder diameter, and the distance from nozzle exit to heater. Conditions of impingement from the bottom (ascending flow) were taken into consideration as well as impingement from above (descending flow). The Nusselt number was determined as a function of Reynolds and Prandtl numbers in the range 1.5 x 103 < Re < 2.0 × 104, 2.7 < Pr < 7.0 and 1.5 < z/Ds < 10. The experimental data were correlated with a simple equation that fits 90% of the data with a precision of 20%.
Uploads
Papers by Reinaldo Ferreira