Modulation spectroscopic investigation on lattice polarity of gallium nitride

Ryuji Katayama, Kentaro Onabe, Hiroyuki Yaguchi, Tomonori Matsushita, Takashi Kondo

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)


A lattice polarity determination method for GaN is demonstrated, which is based on a capability of modulation spectroscopy for the assignment of electric-field directions performed nondestructively using simple optical setups. A strong spontaneous polarization induces an upward band bending toward +c surfaces and a downward but weaker bending toward -c surfaces for typical films with small residual strains and electron densities. This difference is distinguishable in terms of the spectral-phase flip, utilizing photoreflectance, and electroreflectance. Quantitative analysis revealed the exciton dissociation at a high-field region of +c surfaces consistent with the band profile derived as a solution of Poisson equation.

Original languageEnglish
Article number061917
JournalApplied Physics Letters
Issue number6
Publication statusPublished - 2007
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)


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