Polarity inversion of type IIInAs/GaSb superlattice photodiodes

The authors demonstrated the realization of p-on-n type II InAs/GaSb superlattice photodiodes. Growth condition for high quality InAsSb layer lattice matched to GaSb was established for the use of an effective n-contact layer. By studying the effect of various GaSb capping layer thicknesses on the optical and electrical performances, an optimized thickness of 160 nm was determined. In comparison to as grown n-on-p superlattice photodiodes, this inverted design of p on n has shown similar quality. Finally, by analyzing Fabry-Perot interference fringes in the front side illuminated spectral measurement, the refractive index of the superlattice was determined to be approximately 3.8.