Effective minority‐carrier hole confinement of Si‐doped,n⁺‐nGaAs homojunction barriers

The electrical performance of Si-doped n+-n GaAs homojunction barriers grown by molecular-beam epitaxy (MBE) is characterized and analyzed. We employed a successive etch technique to study hole injection currents in GaAs n+-n-p+ solar cells. The results of the analysis show that minority-carrier holes in our MBE-grown material have a mobility of 293 cm2/V s for an n-type Si-doping level of 1.5×1016 cm−3 at 300 K. The interface recombination velocity for these homojunction barriers is estimated to be less than 1×103 cm/s, and it appears to be comparable to that recently observed for Si-doped n+-n GaAs homojunction barriers grown by metalorganic chemical vapor deposition. We present evidence that these n+-n GaAs homojunctions, unlike p+-p GaAs homojunctions, are almost as effective as AlGaAs heterojunctions in minority-carrier confinement, and that their electrical performance is not degraded by heavy doping effects.