MOMBE growth of semi-insulating GaInAsP(λg=1.05 μm):Fe optical waveguides for integrated photonic devices

Iron doping using elemental source material evaporated from a conventional effusion cell was applied during MOMBE growth of semi-insulating InP and GaInAsP(λ=1.05 μm) for waveguide applications. The influence of the growth temperature and the doping concentration on the electrical and optical properties was investigated in the range from 455°C to 505°C and 5·10¹⁵ cm ^-3 to 5·10¹⁵ cm^-3, respectively. High optical quality is demonstrated by the appearance of excitonic emission in iron doped layers at 10 K. Resistivities in excess of 10⁹ Ωcm were obtained for both materials at medium doping levels grown at the lower end of the investigated growth temperature range. In addition, SIMS measurements revealed homogeneous incorporation behaviour of the iron dopant in these materials. A tendency towards some accumulation/segregation of the iron dopant was observed at higher doping levels and growth temperatures resulting in some decrease of the resistivity. GaInAsP/InP waveguide structures grown at 485°C (which is the minimum temperature necessary for selective deposition) showed resistivities of 5·10⁷Ω·cm⁷ in combination with low optical losses of 2.5±0.5 dB/cm