Infrared waveguiding in Si(1-x-y)Ge(x)C(y) upon silicon

Area of Science:

• Materials Science
• Optoelectronics
• Semiconductor Physics

Background:

• Silicon photonics is a rapidly growing field, but achieving polarization-independent waveguiding in silicon-based materials remains a challenge.
• Silicon germanium carbide (SiGeC) alloys offer tunable electronic and optical properties, making them promising candidates for integrated photonic devices.

Purpose of the Study:

• To investigate polarization-independent waveguiding in single-crystal SiGeC grown on silicon.
• To characterize the optical losses and band gap of SiGeC waveguides.

Main Methods:

• Chemical vapor deposition (CVD) was used to grow nearly lattice-matched single-crystal SiGeC on Si(100) substrates.
• Optical transmission measurements were performed at 1.32 and 1.54 micrometers to assess waveguiding properties and losses.
• Spectroscopic ellipsometry or similar techniques were used to determine the band gap of the SiGeC alloys.

Main Results:

• Polarization-independent waveguiding was successfully demonstrated at both 1.32 and 1.54 micrometers.
• Optical losses were measured to be less than 5 dB/cm at 1.54 micrometers.
• The band gap of the SiGeC alloy waveguides was experimentally determined to be in the range of 0.93-0.99 eV, consistent with theoretical predictions.

Conclusions:

• Single-crystal SiGeC grown on silicon is a viable material for polarization-independent optical waveguides.
• The demonstrated low losses and suitable band gap make SiGeC attractive for integrated photonic circuits and telecommunication applications.