Kazuaki Kouyama, Kazuaki Kouyama, Masaya Inoue, Yuta Inose, Naoki Suzuki, Hideyuki Kunugita, Hideyuki Kunugita, Kazuhiro Ema, Kazuhiro Ema, Hiroto Sekiguchi, Hiroto Sekiguchi, Akihiko Kikuchi, Akihiko Kikuchi, Katsumi Kishino, Katsumi Kishino
Physica Status Solidi (C) Current Topics in Solid State Physics, 6(1) 141-143, Apr 6, 2009 Peer-reviewed
We have investigated how the morphology and diameter of GaN nanocolumn affect the optical properties of exciton and biexciton. We measured photoluminescence (PL) of excitons in GaN nanocohinms at low temperature and found that the PL spectra depend on the column diameter. Changing the distance between the sample and the collimatmg lens, it was established that this phenomenon is due to the z-polarized PL radiated from the side surface. This result proves that the nano-scale morphology produces a change in the optical properties. In addition, to elucidate the mechanism causing the increase of the biewciton binding energy observed in a previous experiment, we calculated the exciton binding energies by the variational method and also estimated their sizes. From the calculated results we can expect that the only biexcitons experience spatial confinement effect even when the nanocohimn width is much larger than the exciton Bohr radius. © 2009 WILEY-VCH Verlag GmbH & Co. KGaA.