Composition and strain dependence of the piezoelectric coefficients in semiconductor alloys
T. Hammerschmidt, M. A. Migliorato, D. Powell, A. G. Cullis, G. P. Srivastava.
Material Research Society Symposium Proceedings, 1017, (2007)
We propose a tight-binding model for the polarization that considers direct and dipole contributions and employs microscopic quantities that can be calculated by first-principles methods, e.g. by employing Density Functional Theory (DFT). Applying our model to InxGa1-xAs alloys allows us to settle discrepancies between the values of e14 as obtained from experiments and from linear interpolations between the values of InAs and GaAs. Our calculated piezoelectric coefficient is in very good agreement with photo current measurements of InAs/GaAs(111) quantum well samples.