  The direct growth of III-V semiconductors on silicon holds tremendous
potential for photonics applications. However, the inherent differences in
their properties lead to defects in the epitaxial layer, including threading
dislocations (TDs), antiphase boundaries (APBs), and thermal cracks,
significantly impacting device performance. Current processes struggle to
suppress these defects simultaneously, necessitating the development of methods
to inhibit TDs and APBs in a thin buffer on silicon. This study introduces a
GaSb buffer layer during GaAs epitaxy on a silicon (001) substrate. This
approach successfully suppresses defect formation by promoting the formation of
interfacial misfit dislocation (IMF) arrays at both the AlSb/Si and GaAs/GaSb
interfaces. The resulting GaAs layer exhibits a step-flow surface with a rough
mean square of approximately 3.8 nm and a full width at half maximum of 158
arcsec. Remarkably, the growth is achieved without any observable interfacial
intermixing. Building on this platform, InAs/GaAs quantum dots (QDs) are grown
with a density of 3.8E10/cm2, emitting at a wavelength of 1288 nm. This
breakthrough holds immense promise for developing high-quality GaAs films with
reduced defect densities on silicon for O band lasers, laying the foundation
for the mass production of silicon-based integrated circuits.
