On-Chip Strained Germanium Lasers: A Review.

Area of Science:

• Materials Science
• Nanotechnology
• Photonics

Background:

• Photonic integrated circuits (PICs) are crucial for post-Moore era computing, but lack on-chip CMOS-compatible laser sources.
• Germanium (Ge) straintronics enable bandgap transformation for efficient light emission, essential for integrated lasers.

Purpose of the Study:

• To review the effects of strain on the fundamental physical properties of Ge nanowires.
• To summarize strain engineering methods for Ge nanowires.
• To discuss applications of strained Ge nanowires in on-chip lasers.

Main Methods:

• Discussion of mechanical, electronic, optical, and thermal property changes in strained Ge nanowires.
• Review of established and novel strain engineering techniques.
• Analysis of reported application cases for strained Ge lasers.

Main Results:

• Strain significantly alters Ge nanowire properties, enabling direct bandgap characteristics.
• Various strain engineering methods influence bandgap transformation.
• Strained Ge nanowires show promise for on-chip laser development.

Conclusions:

• Understanding strain effects is critical for advancing Ge-based on-chip lasers.
• This review provides a foundation for future research in strained Ge optoelectronics.
• Effective strain engineering is vital for overcoming current limitations in photonic integrated circuits.