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Proceedings Paper

Epitaxial growth and time-resolved photoluminescence studies of AIN epilayers
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Paper Abstract

AlN epilayers with high optical qualities have been grown on sapphire substrates by metal organic chemical vapor deposition (MOCVD). Deep ultraviolet (UV) photoluminescence (PL) spectroscopy has been employed to probe the optical quality as well as optical transitions in the grown epilayers. Two PL emission lines associated with the donor bound exciton D0X, or I2 and free exciton (FX) transitions have been observed, from which the binding energy of the donor bound excitons in AlN epilayers was determined to be around 16 meV. Time-resolved PL measurements revealed that the recombination lifetimes of the I2 and free exciton transitions in AlN epilayers were around 80 ps and 50 ps, respectively. The temperature dependencies of the free exciton radiative decay lifetime and emission intensity were investigated, from which a value of about 80 meV for the free exciton binding energy in AlN epilayer was deduced. This value is believed to be the largest free exciton binding energy ever reported in semiconductors, implying excitons in AlN are an extremely robust system that would survive well above room temperature. The PL emission properties of AlN have been compared with those of GaN. It was shown that the optical quality as well as quantum efficiency of AlN epilayers is as good as that of GaN. It was shown that the thermal quenching of PL emission intensity is greatly reduced in AlN over GaN, which suggests that the detrimental effect of impurities and dislocations or non-radiative recombination channels in A1N is much less severe than in GaN. The observed physical properties of AlN may considerably expand future prospects for the application of III nitride materials.

Paper Details

Date Published: 30 May 2003
PDF: 7 pages
Proc. SPIE 4992, Ultrafast Phenomena in Semiconductors VII, (30 May 2003); doi: 10.1117/12.479274
Show Author Affiliations
Ki-Bum Nam, Kansas State Univ. (United States)
Jing Li, Kansas State Univ. (United States)
M. L. Nakarmi, Kansas State Univ. (United States)
Jing Yu Lin, Kansas State Univ. (United States)
Hongxing Jiang, Kansas State Univ. (United States)


Published in SPIE Proceedings Vol. 4992:
Ultrafast Phenomena in Semiconductors VII
Kong-Thon F. Tsen; Jin-Joo Song; Hongxing Jiang, Editor(s)

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