| Autor: |
Mendoza-Alvarez, Julio G., Pires, Mauricio P., Landi, Sandra M., Souza, Patricia L., Villas-Boas, Jose M., Studart, Nelson |
| Předmět: |
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| Zdroj: |
AIP Conference Proceedings; 2007, Vol. 885 Issue 1, p240-254, 15p, 1 Chart, 13 Graphs |
| Abstrakt: |
The use of InP substrates has made possible to obtain InAs QD layers with room temperature photoluminescence (PL) in the range 2.0–2.2 μm. This last result was possible because of the shift to lower energies of the InAs QD energy bandgap due to the reduction in the strain field between the InAs and InP, as compared to the case for InAs and GaAs. To study the importance in the control of the strain field between the InAs dots and the beneath layer onto which they are grown, we have used two approximations: 1) Growth of InAs QDs layers on top of InxGa1-xAs layers with variable Stoichiometry; that is, with variable In concentration.; and 2) Growth of InAs QDs layers on top of InxAlyGa1-x-yAs layers with variable Al concentration. In both cases we have used the metal organic vapor phase epitaxy growth technique to grow four-layer structures on top of InP substrates: the first layer being an InP buffer layer, followed by an InxGa1-xAs or InxAlyGa1-x-yAs layer, then a layer of InAs dot material, and finally covered by a InP layer. The control in the parameters of the structure will enable us to control the separation between the first electronic levels in the conduction band of the QD; and so, to control the range of photodetection in the medium infrared between 6 and 8 microns. We show measurements of the low temperature PL spectra for both series of different InAs QDs samples, and through the analysis of these spectra using a 1D effective-mass model for the four-layer structure, we have been able to study the influence of the strain effects for the case of the InxGa1-xAs sublayers, and of the variable potential well for the case of the InxAlyGa1-x-yAs layers. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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