Monolithically Integrated InGaAs Nanowires on 3D Structured Silicon-on-Insulator as a New Platform for Full Optical Links

Abstract

Monolithically integrated III-V semiconductors on a silicon-on-insulator (SOI) platform can be used as a building block for energy-efficient on-chip optical links. Epitaxial growth of III-V semiconductors on silicon, however, has been challenged by the large mismatches in lattice constants and thermal expansion coefficients between epitaxial layers and silicon substrates. Here, we demonstrate for the first time the monolithic integration of InGaAs nanowires on the SOI platform and its feasibility for photonics and optoelectronic applications. InGaAs nanowires are grown not only on a planar SOI layer but also on a 3D structured SOI layer by catalyst-free metal-organic chemical vapor deposition. The precise positioning of nanowires on 3D structures, including waveguides and gratings, reveals the versatility and practicality of the proposed platform. Photoluminescence measurements exhibit that the composition of ternary InGaAs nanowires grown on the SOI layer has wide tunability covering all telecommunication wavelengths from 1.2 to 1.8 μm. We also show that the emission from an optically pumped single nanowire is effectively coupled and transmitted through an SOI waveguide, explicitly showing that this work lays the foundation for a new platform toward energy-efficient optical links.

Composition controllability of InGaAs nanowire arrays in selective area growth with controlled pitches on Si platform

“…This is considered to be the main reason that the diffusion length of In atoms was longer than that of Ga atoms on the SiO 2 mask surface. 12 Moreover, as the Ga composition in the vapor phase increased, the composition in the solid phase tended to correspond to the composition in the vapor phase. This is because the diffusion of In atoms was inhibited by gallium on the mask, and the actual diffusion length of In atoms was shortened.…”

“…11 As mentioned, because the optimum NW pitch depends on the target devices, controlling the composition of InGaAs NWs at various scaled pitches is very important. Photonics and optoelectronic applications monolithically integrating InGaAs NWs on a silicon-on-insulator (SOI) platform have been reported, 12 the NWs pitches are still lacking, particularly on Si substrates and smaller a. Here, we characterized controllability of In content in InGaAs NWs, which have a bandgap compatible with the optical telecommunication bands.…”

Self-Seeded MOCVD Growth and Dramatically Enhanced Photoluminescence of InGaAs/InP Core–Shell Nanowires

“…3a). These planar defects are commonly observed in the growth of InAs or InGaAs nanowires without foreign catalyst by MOCVD [26–28]. Figure 3b shows a bright-field (BF) low-resolution TEM image of a typical InGaAs/InP core−shell nanowire with Xv of 35% (as shown in Fig.…”

Flexible integration of free-standing nanowires into silicon photonics

“…Moreover, benefiting from the bottom-up process that synthesizes nanowires from atomic-size nucleation sites, the nanoscale transverse cross sections of FNWs allow large lattice mismatch in single-crystalline structures 26–28 , which offers much greater material diversity for active and nonlinear applications compared with the traditional top-down technique 29–34 . In order to merge the advantages of the bottom-up and the top-down techniques, previously there have been some successful studies on integrating FNWs with on-chip waveguides 35–37 . The big challenge is to assemble FNWs into functional photonic circuits with low coupling loss and high precision.…”