BAND-OFFSET DEPENDENCE ON IMPACT IONIZATION RATES IN INALGAAS STAIRCASE AVALANCHE PHOTODIODES

Electron (alpha) and hole (beta) impact ionization rates in InAlGaAs s taircase avalanche photodiodes with different sawtooth conduction band offset (Delta E(c)) values mere determined using photomultiplication measurements. The alpha/beta ratio was found to be enhanced from 3.6 t o 5.1 by increasing Delta E(c) from 0.3 eV to 0.5 eV, the largest valu e in this system, under a 470 kV/cm electric field. Internal electric held and hole cooling effects in the distinct sawtooth band structure were studied in relation to the obtained data.