Berlin 2005 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 17: Poster Ib

HL 17.54: Poster

Freitag, 4. März 2005, 16:30–19:00, Poster TU F

Investigation and modelling of the temperature-dependent electronic states in GaNAs and GaInNAs/GaAs quantum well structures — •M. Hetterich¹, A. Grau¹, T. Passow¹, A.Yu. Egorov², and H. Riechert² — ¹Institut für Angewandte Physik and Center for Functional Nanostructures (CFN), Universität Karlsruhe, D-76131 Karlsruhe, Germany — ²Infineon Technologies AG, Corporate Research Photonics, D-81730 München, Germany

Recently, GaInNAs/GaAs has evolved to one of the most promising material systems for the realization of optoelectronic devices operating in the near infrared spectral range. However, many aspects of its electronic structure are still under debate.

In our contribution we investigate the temperature-dependent conduction band structure of GaNAs and GaInNAs/GaAs MQWs with high In concentration using photoreflectance (PR) spectroscopy. The band structure is described using the well-known band anti-crossing (BAC) model. For the BAC wavefunction in general GaInNAs heterostructures we have derived special boundary conditions which are applied to calculate the bound states in the quantum well samples. From the modelling of our experimental data we obtain information about the BAC Hamiltonian parameters. Both the energy of the nitrogen level E_N and the coupling parameter C_NM in the Hamiltonian are found to decrease with increasing temperature. The anti-crossing interaction between E_N and the conduction band leads to a significantly reduced temperature dependence of the band-gap compared to nitrogen-free material.