The formation of double-layer atomic steps on Si(001) surfaces is an efficient way to eliminate the antiphase boundaries (APBs) on GaAs/Si(001) interfaces. The surface energy of on-axis Si(001) surfaces with different atomic step structures was calculated and analyzed from the first principles. An optimal hydrogen-annealing process condition, the hydrogen pressure of 800 mbar and the annealing temperature of 800 °C for 10 min, was obtained experimentally. Under this annealing condition, a 420 nm APB-free GaAs epitaxial layer grown on on-axis Si(001) substrates was achieved by metal-organic chemical vapor deposition. The effect of the annealing temperature on the APB density of the GaAs/Si(001) samples was explained from the aspects of thermodynamics and kinetics. It is of great significance to optimize the growth conditions of APB-free III–V epitaxial materials on on-axis Si(001) surfaces for the large-scale silicon monolithic integration of optoelectronic devices.

No abstract

We optimize the structure of a silicon-based InAs/InGaAs quantum dot square microcavity laser with an output waveguide structure. By designing a new laser structure, the emission wavelength is extended to 1550 nm. We investigate the structure parameters that affect the quality factor and optical mode of the square microcavity, including the side length of the microcavity, the width of the output waveguide, the cladding layer thickness and the etching depth. By connecting the output waveguide at the edge-midpoint of the square microcavity, both the unidirectional emission and mode selectivity can be obtained, which avoids mode competition. The 1550 nm wavelength single-mode laser is beneficial and has reat significance for the development of silicon-based optoelectronic integration.

We demonstrate an optimized structure design and analyze the optical mode characteristics of 1.55 μm Si-based III-V square microcavity laser with InAs/InGaAs quantum-dot active region and directional midpoint output waveguide.

No abstract