Free exciton emission in GaN

Kovalev, D.; Averboukh, B.; Volm, D.; Meyer, B. K.; Amano, Hiroshi; Akasaki, Isamu

doi:10.1103/physrevb.54.2518

Cited by 140 publications

(79 citation statements)

References 13 publications

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“…The temperature dependence of this process reveals acoustic phonon emission as the rate determining step, suggesting that exciton formation occurs from cold charges, in contrast to previous suggestions that "hot" excitons are formed. 7 Above the Mott density, we observe a very rapid ͑ϳ1.5 ps͒ decay of the electron-hole plasma through Auger annihilation. In contrast to exciton formation, the annihilation occurs while the plasma is still hot, and is found to be independent of lattice temperature.…”

Section: Introductionmentioning

confidence: 75%

“…11 The observation that this process occurs on relatively long time scales in bulk ZnO is remarkable given the hypothesis that the emissive exciton is formed through a "hot exciton cascade." 7 In this picture, photon absorption followed by rapid emission of optical phonons by photocarriers leads to the formation of hot excitons, which subsequently cool to the emissive ͑K =0͒ state by slow acoustic phonon emission ͓Fig. 5͑a͔͒.…”

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confidence: 99%

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Exciton and electron-hole plasma formation dynamics in ZnO

2007

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We employ optical pump-THz probe measurements to study the formation of excitons and electron-hole plasmas following photogeneration of a hot electron-hole gas in the direct gap semiconductor zinc oxide. Below the Mott density, we directly observe the evolution of the hot electron-hole plasma into an insulating exciton gas in the 10 to 100 ps following photoexcitation. The temperature dependence of this process reveals that the rate determining step for exciton formation involves acoustic phonon emission. Above the Mott density, the density of the hot electron-hole plasma initially decreases very rapidly ͑ϳ1.5 ps͒ through Auger annihilation until a stable plasma is formed close to the Mott density. In contrast to exciton formation, Auger annihilation is found to be independent of lattice temperature, occurring while the plasma is still hot.

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Section: Introductionmentioning

confidence: 75%

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confidence: 99%

Exciton and electron-hole plasma formation dynamics in ZnO

2007

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“…We note that the DBE PL features in GaN are stable up to much higher temperatures, e.g., 150 K in samples with low doping. 22 In order to obtain a complete experimental picture, the spectra from an 11-lm-thick HVPE grown GaN:Mg layer on sapphire was studied as well, as shown in Fig. 3.…”

Section: à3mentioning

confidence: 99%

Properties of the main Mg-related acceptors in GaN from optical and structural studies

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Paskov

Pozina

et al. 2014

Journal of Applied Physics

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), the 3.466 eV ABE1 acceptor bound exciton and the associated 3.27 eV donor-acceptor pair (DAP) band are the only strong photoluminescence (PL) signals at 2 K, and are identified as related to the substitutional Mg acceptor with a binding energy of 0.225 6 0.005 eV, and with a moderate phonon coupling strength. Interaction between basal plane stacking faults (BSFs) and Mg acceptors is suggested to give rise to a second deeper Mg acceptor species, with optical signatures ABE2 at 3.455 eV and a corresponding weak and broad DAP peak at about 3.15 eV. The 2.9 eV PL band has been ascribed to many different processes in the literature. It might be correlated with another deep level having a low concentration, only prominent at high Mg doping in material grown by the Metal Organic Chemical Vapor Deposition technique. The origin of the low temperature metastability of the Mg-related luminescence observed by many authors is here reinterpreted and explained as related to a separate non-radiative metastable deep level defect, i.e., not the Mg Ga acceptor. V C 2014 AIP Publishing LLC. [http://dx

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“…The coupling of LO phonons with free and bound excitons in GaN has been measured previously [1,2]. There was also reported the temperature dependence of LO-phonon replicas of free excitons in heteroepitaxial and homoepitaxial GaN layers [3].…”

Section: Introductionmentioning

confidence: 95%