Si δ-doping superlattices in InP grown by low-pressure metalorganic vapor phase epitaxy

Single Si delta-doped InP samples were grown at 640 degrees C with different doping concentrations. A full width at half maximum for the net charge concentration profile of 32 Angstrom was obtained, which corresponds to an impurity localization over less than 8 Angstrom according to numerical simulations. No dopant diffusion or segregation was observed. A series of periodically Si delta-doped InP structures with 5 and 10 periods varying from 92 to 278 Angstrom has been investigated. A reduction in mobility with decreasing period was observed due to the increasing overlap of the electronic wavefunction with the various Si planes. A broad band photoluminescence emission was detected for the periodic structures at energies higher than the InP band gap. Its intensity decreases with a reduction in the period indicating the 3D character of the sample. The cutoff energy for this band decreases with the period and this behavior can be described by a d(-2/3) decay which is expected from a 3-dimensional system.