Effect of gas-phase stoichiometry on the minority-carrier diffusion length in vapor-grown GaAs

Abstract

The electron diffusion length in Zn-doped (p ∼1×1019 cm−3) vapor-grown GaAs has been found to depend strongly on the gas-phase stoichiometry used during epitaxial deposition. Specifically, near-stoichiometric or Ga-rich flow conditions provide diffusion lengths as large as 4.8 μm; this is about a factor of two larger than that of VPE GaAs prepared under commonly used As-rich flow conditions, and is comparable to that of LPE GaAs. Furthermore, the modified gas-flow conditions provide reduced threshold current densities for a room-temperature double-heterojunction laser of GaAs/In0.5Ga0.5P.