Photoconductivity and electroreflectance study of cubic GaN/GaAs(001) heterostructures by optical-biasing technique

Ryuji Katayama, M. Kuroda, K. Onabe, Y. Shiraki

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2 Citations (Scopus)


Photoconductivity (PC) and electroreflectance (ER) spectrum measurements were carried out for the cubic GaN/GaAs and cubic AlGaN/GaN/GaAs heterostructures grown by LP-MOVPE. Both spectra contained significantly overlapped signals from the c-(Al)GaN epitaxial layer and the underlying GaAs layer, but the latter was successfully suppressed and distinguished from the former by the use of an additional steady-state illumination of Ar+ laser as an optical bias. The temperature dependence of the optically-biased PC spectrum showed that there remained structural disorder in the c-GaN layer indicated by the temperature-independent Urbach energy. From the temperature dependence of the ER spectrum, the E0 critical point of c-GaN observed likely corresponds not to excitonic transition but to free-carrier transition as it shifted by ∼30 meV to higher energies than the reported value, probably due to the dissociation of exciton by the relatively large modulation field applied to the c-(Al)GaN layer.

Original languageEnglish
Pages (from-to)877-881
Number of pages5
JournalPhysica Status Solidi (B) Basic Research
Issue number3
Publication statusPublished - 2002 Dec 1

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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