Determination of absolute value of quantum efficiency of radiation in high quality GaN single crystals using an integrating sphere

Kazunobu Kojima, Tomomi Ohtomo, Ken Ichiro Ikemura, Yoshiki Yamazaki, Makoto Saito, Hirotaka Ikeda, Kenji Fujito, Shigefusa F. Chichibu

研究成果: Article査読

24 被引用数 (Scopus)

抄録

Omnidirectional photoluminescence (ODPL) measurement using an integrating sphere was carried out to absolutely quantify the quantum efficiency of radiation (η) in high quality GaN single crystals. The total numbers of photons belonging to photoluminescence (PL photons) and photons belonging to an excitation source (excitation photons) were simultaneously counted in the measurement, and η was defined as a ratio of the number of PL photons to the number of absorbed excitation photons. The ODPL spectra near the band edge commonly showed a two-peak structure, which originates from the sharp absorption edge of GaN. A methodology for quantifying internal quantum efficiency (ηint) from such experimentally obtained η is derived. A record high ηint of typically 15% is obtained for a freestanding GaN crystal grown by hydride vapor phase epitaxy on a GaN seed crystal synthesized by the ammonothermal method using an acidic mineralizer, when the excitation photon energy and power density were 3.81 eV and 60 W/cm2, respectively.

本文言語English
論文番号015704
ジャーナルJournal of Applied Physics
120
1
DOI
出版ステータスPublished - 2016 7月 7

ASJC Scopus subject areas

  • 物理学および天文学(全般)

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