Spontaneous versus piezoelectric polarization in III-V nitrides: Conceptual aspects and practical consequences

Macroscopic polarization plays a major role in determining the optical and electrical properties of nitride nanostructures via polarization-induced bu ilt-in electrostatic fields. While currently fashionable, this field of end eavour is still by far in its early infancy. Here we contribute some clarif ications on the conceptual issues involved in determining built-in fields i n III-V nitride nanostructures, sorting out in particular the roles of spon taneous and piezoelectric polarization.