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

We report use of InAs/AlSb superlattice as the n-type layer in an all molec ular beam epitaxially grown, antimonide avalanche photodetector. N-type dop ing of the superlattice was achieved by selectively incorporating Si in the InAs layer. The superlattice was grown lattice matched to the GaSb substra te and exhibited sharp X-ray diffraction satellite peaks. By using the supe rlattice as part of the one-sided abrupt junction, p(-)n(+) avalanche photo diodes with Al,.,,Ga,,,Sb multiplication regions were fabricated. The devic e dark current was found to be highly dependent on the superlattice period and the resulting band offset at the superlattice/multiplication layer inte rface. 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 optim ized, there stage InAs/AlSb superlattice. (C) 2000 Elsevier Science B.V. Al l rights reserved.