Optical properties of heavily doped GaN/(Al,Ga)N multiple quantum wells grown on 6H-SiC(0001) by reactive molecular-beam epitaxy

We study, both experimentally and theoretically, the influence of polarizat ion-induced electric fields on the optical properties of heavily doped (7 x 10(18) cm(-3)) GaN/(Al,Ga)N multiple-quantum-well structures. To investiga te the impact of the strain state on the transition energy, these heterostr uctures are deposited on either a GaN or an (Al,Ga)N relaxed buffer layer. Furthermore, we show that the recombination dynamics in these heavily doped multiple quantum wells is still controlled by residual electric fields, co ntrary to the common assumption that flatband conditions are established at this doping level.