TY - JOUR
T1 - Correlation between the violet luminescence intensity and defect density in AlN epilayers grown by ammonia-source molecular beam epitaxy
AU - Hoshi, Takuya
AU - Koyama, Takahiro
AU - Sugawara, Mariko
AU - Uedono, Akira
AU - Kaeding, John F.
AU - Sharma, Rajat
AU - Nakamura, Shuji
AU - Chichibu, Shigefusa F.
PY - 2008
Y1 - 2008
N2 - Intensity ratios of deep cathodoluminescence (CL) bands at 4.6, 3.8 and 3.1 eV to the near-band-edge emission of AlN epilayers grown by NH 3-source molecular beam epitaxy were correlated with the change in S parameter of positron annihilation measurement, which represents the concentration or size of Al vacancies (VAl). The origins of the deep emission bands were assigned to donor-acceptor pairs associated with V Al and/or VAl-defect complexes. The VAl concentration was decreased by adjusting the flux ratio of NH3 to Al and growth temperature, resulting in observation of fine excitonic features in the CL spectra. From the energy separation between the ground and first excited states, the binding energy of free A-exciton was estimated to be 48 meV.
AB - Intensity ratios of deep cathodoluminescence (CL) bands at 4.6, 3.8 and 3.1 eV to the near-band-edge emission of AlN epilayers grown by NH 3-source molecular beam epitaxy were correlated with the change in S parameter of positron annihilation measurement, which represents the concentration or size of Al vacancies (VAl). The origins of the deep emission bands were assigned to donor-acceptor pairs associated with V Al and/or VAl-defect complexes. The VAl concentration was decreased by adjusting the flux ratio of NH3 to Al and growth temperature, resulting in observation of fine excitonic features in the CL spectra. From the energy separation between the ground and first excited states, the binding energy of free A-exciton was estimated to be 48 meV.
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U2 - 10.1002/pssc.200778473
DO - 10.1002/pssc.200778473
M3 - Conference article
AN - SCOPUS:67649207297
SN - 1862-6351
VL - 5
SP - 2129
EP - 2132
JO - Physica Status Solidi (C) Current Topics in Solid State Physics
JF - Physica Status Solidi (C) Current Topics in Solid State Physics
IS - 6
T2 - 7th International Conference of Nitride Semiconductors, ICNS-7
Y2 - 16 September 2007 through 21 September 2007
ER -