Ryo Nakao

Epitaxial growth on lattice-mismatched substrate for high-performance lasers

Heteroepitaxial, or metamorphic, growth enables us to overcome limitations on the performance of semiconductor devices caused by the lattice-matching restriction. We have demonstrated high-crystalline-quality metamorphic grown InGaAs and GaAs/Ge layers on GaAs and Si substrates, respectively. The InGaAs layer on GaAs allows us to make laser diodes operating at 25 Gbit/s with high characteristic temperature of 187 K at 1.3-μm wavelength. Moreover, III-V compound semiconductors on Si substrate are promising to for large-scale and low-cost fabrication. We have also achieved a high-crystalline-quality GaAs layer on Si substrate by using an MOVPE-grown Ge buffer layer.