Minority carrier diffusion length and recombination lifetime in GaAs:Ge prepared by liquid-phase epitaxy

The electron diffusion length in p-type GaAs:Ge grown by liquid-phase epitaxy has been measured as a function of hole concentration. The direct measurements were made by two different techniques —a laser beam scan on beveled samples and an α particle scan on cleaved samples. These measurements are in good agreement and show that the diffusion length increases from ∼6 μm at p=1×1019 cm−3 to ∼20 μm at p=7×1016 cm−3. In addition, the diffusion length was estimated from electroluminescent decay times of p-n junctions and the values obtained were in reasonable agreement with those directly measured for the same materials.