Comparative study of minority electron properties in p+-GaAs doped with beryllium and carbon

Minority electron properties in p+-GaAs doped with beryllium (Be) and with carbon (C) are reported. Measurements of essentially identical responses for structures differing only in dopant element demonstrate that the diffusivity (Dn) and the diffusion lengths (Ln) are the same in p+-GaAs doped to ∼1019 cm−3 with Be- and C-dopants. Zero-field time-of-flight analysis yields Dn=35 cm2/s and internal quantum efficiency analysis yields Ln=2.4 μm, which implies a lifetime that is approximately at the estimated radiative limit. In addition, the majority Hall mobility was also found to be identical for the Be- and C-doped material.