@Article{Corfdir_prb_2014,
Title = {Stacking faults as quantum wells in nanowires: Density of states, oscillator strength, and radiative efficiency},
Author = {Corfdir, P. and Hauswald, C. and Zettler, J. K. and Flissikowski, T. and L\"ahnemann, J. and Fern\'andez-Garrido, S. and Geelhaar, L. and Grahn, H. T. and Brandt, O.},
Journal = {Phys. Rev. B},
Volume = {90},
Number = {19},
Pages = {195309},
Year = {2014},
Abstract = {We investigate the nature of excitons bound to I1 basal-plane stacking faults [(I1,X)] in GaN nanowire ensembles by continuous-wave and time-resolved photoluminescence spectroscopy. Based on the linear increase of the radiative lifetime of these excitons with temperature, they are demonstrated to exhibit a two-dimensional density of states, i.e., a basal-plane stacking fault acts as a quantum well. From the slope of the linear increase, we determine the oscillator strength of the (I1,X) and show that the value obtained reflects the presence of large internal electrostatic fields across the stacking fault. While the recombination of donor-bound and free excitons in the GaN nanowire ensemble is dominated by nonradiative phenonema already at 10 K, we observe that the (I1,X) recombines purely radiatively up to 60 K. This finding provides important insight into the nonradiative recombination processes in GaN nanowires. First, the radiative lifetime of about 6 ns measured at 60 K sets an upper limit for the surface recombination velocity of 210cms−1 considering the nanowires mean diameter of 50 nm. Second, the density of nonradiative centers responsible for the fast decay of donor-bound and free excitons cannot be higher than 6×1016 cm−3. As a consequence, the nonradiative decay of donor-bound excitons in these GaN nanowire ensembles has to occur indirectly via the free exciton state.},
Arxiv = {1408.5263},
Doi = {10.1103/PhysRevB.90.195309}
}