Electroabsorption avalanche photodiodes

Abstract

Schottky barrier avalanche photodiodes have been fabricated on n-type high-purity epitaxial GaAs. These devices have their largest response at wavelengths beyond the usual absorption edge for high-purity materials. The absorption mechanism involves the Franz-Keldysh shift of the absorption edge, and the higher response at the longer wavelengths can be explained by a much higher ionization coefficient for holes than for electrons. The results indicate that the ratio of βp to αn is even larger than previous measurements have given.