Impact ionization coefficients in InGaAs/GaAs strained layer multiple quantum well structures

Strained layer superlattices (SLS) comprise two materials of different lattice parameters and therefore have the flexibility of mismatched compositions provided that certain constraints on the thicknesses are observed. To use these SLS systems in avalanche photodetectors (APD´s) one needs to know the effective electron (α) and hole (β) ionization coefficients. The material system examined is InGaAs/GaAs grown on a GaAs substrate. Experimental results indicate that strained layer systems should be considered seriously for APD´s and that the strain does not appear to degrade the optical and electrical characteristics