| Autor: |
Mendoza-Alvarez, Julio G., Pires, Mauricio P., Landi, Sandra M., Souza, Patricia L., Villas-Boas, Jose M., Studart, Nelson |
| Předmět: |
|
| Zdroj: |
AIP Conference Proceedings; 2007, Vol. 893 Issue 1, p943-944, 2p, 3 Graphs |
| Abstrakt: |
In this paper we report on the growth, using MOVPE (Metal Organic Vapor Phase Epitaxy), of a layer of InAs quantum dots (QDs) on top of quaternary layers of In0.53AlyGa0.47-yAs lattice-matched to InP substrates, with a variable Stoichiometry due to the variation in the Al concentration. It has been recently reported that as the Al concentration in the quaternary layer increases, smaller InAs QDs are obtained, and also that the peak of the luminescence emission shifts to longer wavelengths up to around 2.1 microns. In this work we present results on the PL characterization for a set of InAs QDs/In0.53AlyGa0.43-yAs samples, for aluminum concentrations of y = 0, 0.058, 0.11 and 0.165. PL spectra were measured changing the laser excitation power and the sample temperature in the range from 16K up to room temperature. From the analysis of the PL spectra we observe that at low temperatures the emission band is composed of two contributions centered at around 0.64 and 0.673 eV which shift to higher energies as the Al concentration in the layer increases as a result of the increase in the energy barrier height between the dot and the InAlGaAs layer. We discuss the nature of the transitions involved in the PL bands and their behavior with the laser power and temperature, using a 1D theoretical model that takes into account the energy position of the quantized electronic levels in the InAs QDs due to the band offsets and to the strain effects at the InAlGaAs-InAsQD-InP interfaces. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
|
