Impacts of dislocation bending and impurity incorporation on the local cathodoluminescence spectra of GaN grown by ammonothermal method

S. F. Chichibu, T. Onuma, T. Hashimoto, K. Fujito, F. Wu, J. S. Speck, S. Nakamura

研究成果: Article査読

14 被引用数 (Scopus)

抄録

Spatially resolved cathodoluminescence (CL) spectra of GaN films grown on freestanding GaN seeds via fluid transport by the ammonothermal method were correlated with the microstructure and growth polarity. The spectral line shape of local CL was nearly position independent for a 4-μm -thick N-polar film exhibiting featureless morphology. The spectra exclusively exhibited a broad near-band-edge (NBE) free carrier recombination emission with Burstein-Moss shift. Conversely, CL spectra at 100 K of a 5-μm -thick Ga-polar film having (10 1- 1) and (10 1- 2) facets with ridges originating from central pits exhibited a NBE peak at 3.444 eV and emission bands at 3.27, 2.92, and 2.22 eV, all of which showed rich intensity contrasts in the CL mapping images. The NBE peak intensity was remarkably enhanced at crests of the ridges, where the density of threading dislocations (TDs) having edge components was greatly reduced by the dislocation bending. The results encourage one to grow low TD density GaN wafers by slicing thick crystals grown by the ammonothermal method.

本文言語English
論文番号251911
ジャーナルApplied Physics Letters
91
25
DOI
出版ステータスPublished - 2007
外部発表はい

ASJC Scopus subject areas

  • 物理学および天文学(その他)

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