Fluctuations of piezoelectric polarization in III-nitride quantum wells

n this work, the influence of the atomic disorder on a local piezoelectric polarization in polar II-nitride quantum wells is simulated. The calculation is performed for GaN/InGaN/GaN structures with a random distribution of In atoms in the quantum well region. The key component of the research is the valence force field model optimized for nitrides, which is used to obtain the distribution of relaxed atomic positions and the local strain tensor. The calculation showed a strong spatial non-uniformity of the piezoelectric polarization, which can even change the sign of the local polarization value and makes the distribution of a polarization potential substantially different from the standard capacitor-like picture that is observed in the case of constant polarization vectors in the quantum well and barriers. (author)