Optical nonlinearities of gallium nitride

(Hyper)polarizabilities of GaN, GaP, and GaAs Clusters: An Ab Initio Time-Dependent Hartree−Fock Study

“…[8][9][10] Very recently, Schlecht et al 11 and Scha ¨fer et al 12 have reported the electric dipole polarizability of isolated GaAs clusters. It has been suggested that impurities and defects 13 can have a significant effect on the optical nonlinearities of these materials. Therefore, an understanding of the basic mechanism of NLO response and its relationship with the microscopic features of group III-V clusters is considered important and timely.…”

“…Recent advances in experimental techniques to synthesize and analyze stable clusters composed of group III−V elements have generated a great deal of interest in the NLO properties of these chemically engineered species. − Very recently, Schlecht et al and Schäfer et al have reported the electric dipole polarizability of isolated GaAs clusters. It has been suggested that impurities and defects can have a significant effect on the optical nonlinearities of these materials. Therefore, an understanding of the basic mechanism of NLO response and its relationship with the microscopic features of group III−V clusters is considered important and timely.…”

Influence de la saturation des niveaux d'impuretés sur la dynamique de la luminescence de couches épitaxiées de nitrure de gallium

“…Ces niveaux correspondraient à des centres profonds, situés 1 eV au-dessus de la bande de valence et seraient dus à des impuretés (oxygène ou carbone) ou à des défauts structuraux [6] À faible intensité, la solution du système (1) pour la densité de porteurs de la bande de conduction ne est une double exponentielle, ce qui est en accord avec l'expérience. Le temps de recombinaison des porteurs de la bande de conduction ayant été déterminé précédemment par des mesures de mélange d'ondes [7], nous attribuons le temps de 25 ps au temps de relaxation des porteurs de la bande de conduction vers les différents états localisés (T"' =T~CP +Tç,).…”

Long coherent dynamics of localized excitons in (In,Ga)N/GaN quantum wells

“…This is important and lacking information, since most studies of exciton localization in (In,Ga)N/GaN QWs have focused so far on the measurement of microphotoluminescence (PL) lines from the individual localized exciton states at low temperatures [9,10]. Only a few works are known where four-wave mixing techniques were applied to study the coherence of excitons in GaN bulk [11,12], epilayers [13,14] and GaN-based QWs [15,16]. In particular, exciton dephasing times as short as T 2 ∼ 300 fs were measured by the photon echo technique in a 120 nm GaN film at temperature T = 10 K [13].…”