Molecular beam epitaxy growth of antimonide avalanche photodetectors with InAs/AlSb superlattice as the n-type layer

Abstract

We report use of InAs/AlSb superlattice as the n-type layer in an all molecular beam epitaxially grown, antimonide avalanche photodetector. N-type doping of the superlattice was achieved by selectively incorporating Si in the InAs layer. The superlattice was grown lattice matched to the GaSb substrate and exhibited sharp X-ray diffraction satellite peaks. By using the superlattice as part of the one-sided abrupt junction, p −n + avalanche photodiodes with Al 0.04Ga 0.96Sb multiplication regions were fabricated. The device dark current was found to be highly dependent on the superlattice period and the resulting band offset at the superlattice/multiplication layer interface. Near infrared photo gains of up to 30 and a dark current density of 6 A/cm 2 at a gain factor of 10 were observed for structures with an optimized, there stage InAs/AlSb superlattice.