interface quality between GaAs/Si vs GaAs/GaAlAs

Thread Starter


Joined Mar 22, 2011
Hey everyone, I have a question relating to surface recombination velocity. I assume that the interface of GaAs/Si would produce a lower quality than between GaAs/GaAlAs due to the fact that my notes state that GaAs/GaAlAs is most common in double heterostructure for lasers. I would like to know why this is the case (if my prediction is correct). Is it just a geological problem such as the interface between GaAs/Si has more defects and thus a higher non-radiative recombination rate?

I was thinking along the lines of the difference in band gaps: GaAs has an energy gap of around 1.42 eV, AlGaAs 1.79 eV and Si 1.1 eV. By looking at the differences between the two, GaAs/GaAlAs would have a band gap of 0.37 eV and GaAs/Si 0.32 eV. I don't think this will help with my above question but was wondering what this could tell me about the device.