Surfactant effects on GaAs-Ge heterostructures

A study of the effect of isoelectronic surfactants (In and P) on the photoluminescence and photovoltaic characteristics of GaAs-Ge heterostructures is presented. The surfactants were introduced into the structure by simultaneous post-growth diffusion. A GaAs photoluminescence spectra analysis was performed via a layer-by-layer etching procedure. It is shown that the effect of the surfactants is observed over a wide concentration range from 3×1017 to 1×1020 cm−3. The effects of the In and P passivation of nonradiative recombination centers are observed. A p-n junction was formed via phosphorus diffusion. PV conversion efficiency of 3.2% for the 900-1840 nm wavelength region has been registered under 40-400x concentrated sunlight (AM1.5D low-AOD).