Field dependence of impact ionization coefficients in In0.53Ga0.47As

Electron and hole ionization coefficients in In_0.53Ga_0.47As are deduced from mixed carrier avalanche photomultiplication measurements on a series of p-i-n diode layers, eliminating other effects that can lead to an increase in photocurrent with reverse bias. Low field ionization is observed for electrons but not for holes, resulting in a larger ratio of ionization coefficients, even at moderately high electric fields than previously reported. The measured ionization coefficients are marginally lower than those of GaAs for fields above 250 kVcm^-1, supporting reports of slightly higher avalanche breakdown voltages in In_0.53Ga_0.47As than in GaAs p-i-n diodes.