Impact ionization rates in an InGaAs/InAlAs superlattice

Abstract

An In0.53Ga0.47As/In0.52Al0.48As superlattice avalanche photodiode is fabricated by molecular beam epitaxy, and ionization rates are measured. The electron ionization rate is enhanced by a factor of 20 over hole ionization rate. This is the first time that such a remarkable increase has been observed for a superlattice. The increase is attributed to the large conduction-band offset.