Regensburg 2004 – scientific programme

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HL: Halbleiterphysik

HL 25: Heterostrukturen II

HL 25.5: Talk

Tuesday, March 9, 2004, 19:00–19:15, H14

Relaxation times in type I and type II (Ga,In)As/Ga(N,As) quantum wells — •K Hantke, J. D. Heber, H. Grüning, P. J. Klar, W. Heimbrodt, J. Koch, S. Nau, W. Stolz, and W. W. Rühle — FB Physik und WZMW, Philipps-Universität Marburg, 35032 Marburg

The incorporation of small quantities of nitrogen into GaAs or (Ga,In)As leads to a strong red shift of the band gap due to a level repulsion between the localized nitrogen level above the conduction band edge and the conduction band of the host material itself. Therefore, emitters in the technologically important wavelength region around 1.3 µm can be realized with these materials. The influence of this incorporation of nitrogen on the conduction band discontinuity of (Ga,In)As/Ga(N,As) quantum wells was determined as a function of temperature and excitation density by time-resolved photoluminescence measurements. With increasing nitrogen concentration in the barriers, ranging from about 0.48% to 2.2%, a switch in band-offset from type I to type IIb was found. At intermediate nitrogen concentrations of around 0.75% to 1.25% the actual band-offset is shown to strongly depend on temperature and excitation density.