Effects of built-in electric field on polarons in wurtzite GaN/AlN quantum wells

Within the framework of the dielectric continuum model and Loudon's uniaxial crystal model, we derive the correct solutions to the half-space optical-phonon modes in strained wurtzite GaN/AlN quantum wells. Considering the strong built-in electric field induced by the spontaneous and piezoelectric polarization, we investigate the intermediate-coupling polaron effects in GaN/AlN quantum wells by means of a coordinate-dependent Lee-Low-Pines variational approach. Our results show that the polaron energy shifts due to the various optical-phonon modes are changed greatly in comparison with the case of neglecting the built-in electric field. For quantum wells with realistic well-width (>3nm), the total polaron energy shift mainly comes from the contribution of the interface modes (∼75%∼75%) instead of the confined modes (∼20%∼20%) which is dominant in the case of neglecting the built-in electric field.