Exciton spectra of an AlN epitaxial film on (0001) sapphire substrate grown by low-pressure metalorganic vapor phase epitaxy

Autor:	Takayuki Sota, Tomohiko Shibata, Keiichiro Asai, Shigeaki Sumiya, Mitsuhiro Tanaka, Takeyoshi Onuma, Shigefusa F. Chichibu
Rok vydání:	2002
Předmět:	Materials science Physics and Astronomy (miscellaneous) Phonon business.industry Exciton Cathodoluminescence Epitaxy Molecular physics Spectral line shape Crystal Condensed Matter::Materials Science Optoelectronics Thin film business Bohr radius
Zdroj:	Applied Physics Letters. 81:652-654
ISSN:	1077-3118 0003-6951
DOI:	10.1063/1.1493666
Popis:	Exciton resonance energies in an AlN epilayer on (0001) sapphire substrate grown by low-pressure metalorganic vapor phase epitaxy were determined as a function of temperature by means of optical reflectance (OR) and cathodoluminescence measurements. The OR spectra exhibited distinct reflectance anomalies at the photon energies just above the multiple internal reflection fringes, and the spectral line shape was fitted considering A (Γ7vu→Γ7c) and BC (Γ9v,Γ7vl→Γ7c) exciton transitions. The fitting gave the values of them at 0 K to be 6.211 and 6.266 eV, giving the crystal- field splitting (Δcr) of approximately 55 meV. The AlN film exhibited an excitonic emission even at 300 K, which is due to the small Bohr radius of excitons and large longitudinal optical phonon energies. The Einstein characteristic temperature ΘE was estimated to be 580 K.
Databáze:	OpenAIRE
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