Wurtzitic semiconductors heterostructures grown on (hk.ℓ) oriented substrates: the interplay between spontaneous and piezoelectric polarization fields, elastic energy, and the modification of quantum confined Stark effect

Abstract

The equations appropriate to calculate spontaneous and piezoelectric polarization fields at heterointerfaces of wurtzitic semiconductors grown on any (hk.ℓ) planes are presented in the context of a description that fulfils the prescriptions of crystallography and elasticity theory. Some specific crystal orientations may lead to a cancellation of the Quantum Confined Stark Effect in such heterostructures. The angle between the normal to these orientations and (0001) is not constant and depends on h, k and ℓ. These crystal orientations do not correspond to a minimization of the elastic energy stored in the strained layers. The impact of this reduction or cancellation of the QCSE is discussed, computed and compared with fresh experimental data collected in case of devices grown on non polar and semi polar substrates for the GaInN-GaN combination.