Mesoscopic-capacitor effect in GaN/AlxGa1-xN quantum wells: Effects on theelectronic states - art. no. 235305

We show that wide GaN quantum wells behave Like mesoscopic capacitors. The electron-hole pairs are separated by the spontaneous and piezoelectric pola rization fields and accumulated in the well, resulting in a well-width depe ndent screening of the built-in field. The extent to which such screening i s effective depends on the interplay between radiative and nonradiative rec ombination probabilities, which deplete the ground level of the quantum wel l, causing the recovery of the unscreened built-in field. The account of th e mesoscopic capacitor effect provides a quantitative description of the op tical spectra and of the time dynamics of a set of high quality quantum wel ls with well characterized structural parameters.