Effects of stoichiometry and Te concentration on the deep levels in liquid-phase epitaxially grown n-type Al0.3Ga0.7As

Jun Ichi Nishizawa, Akihiko Murai, Yutaka Oyama, Ken Suto

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2 Citations (Scopus)


Photocapacitance (PHCAP) and Hall effect measurements are applied to liquid-phase epitaxially grown n-Al0.3Ga0.7As crystals, followed by an annealing at 900°C for 1 h under controlled arsenic vapor pressure. Photocapacitance measurements reveal two deep levels in relatively lightly Te-doped samples, the optical activation energy of which are 0.5 and 1.1 eV, respectively (Ec-0.5 eV level and Ec-1.1 eV level). The Ec-0.5 eV level density increases with applied arsenic vapor pressure during annealing. The Ec-1.1 eV level density increases with increasing arsenic vapor pressure, but decreases at the highest arsenic vapor pressures. Hall effect measurements show that activation ratio between carrier concentration and Te concentration is higher when the epitaxial layers are annealed under lower arsenic vapor pressure (0.2 Torr) than the samples annealed under higher arsenic pressure (310 Torr), and decreases in the heavily Te-doped samples. From these results, the origin of the defects detected in n-AlxGa1-xAs is discussed in view of deviation from the stoichiometric composition and Te doping in the AlxGa1-xAs ternary alloy system.

Original languageEnglish
Pages (from-to)2905-2909
Number of pages5
JournalJournal of the Electrochemical Society
Issue number8
Publication statusPublished - 1998 Aug

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Surfaces, Coatings and Films
  • Electrochemistry
  • Materials Chemistry

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