Thursday, September 17, 2026
4:00 pm-5:00 pm
Advanced Molecular Beam Epitaxy Growth Techniques for Sn-containing Group-IV Infrared Materials
The Group-IV material system, including Si, Ge, and their alloys, has formed the backbone of the
semiconductor industry for over half a century. Si-based CMOS devices have defined the current landscape
of cutting-edge semiconductor devices, accounting for over 99% of global semiconductor fabrication.
However, the indirect bandgaps of both Si and Ge fundamentally limit their use in optoelectronic
applications. More recently, introducing α-Sn, the diamond-structure phase of Sn, into the group-IV alloy
system has enabled tunable bandgaps, expanding desirable electronic and optical properties, including
expansion in the infrared spectrum. Progress in maturing the GeSn materials remains challenging due to
complex thermodynamic and kinetic constraints in growing Sn-containing alloys, such as the low
equilibrium solubility of Sn, the presence of a miscibility gap, and significant lattice mismatches with
commercially available substrates. This symposium will highlight how advanced semiconductor growth
techniques utilizing molecular beam epitaxy are being leveraged to address these challenges, through the
growth of SiGe/GeSn superlattices. Superlattices composed of these Group-IV elements and alloys provide
a platform for achieving higher Sn incorporation and low-defect density through strain engineering. This
technique also allows additional degrees of freedom for band-structure design and for controlling alloy
composition profiles for device applications and materials physics studies. These structures serve as a
platform for future investigation of the optical performance of the GeSn material system in the infrared
spectrum.
