Solving thermal issues in tensile-strained Ge microdisks.

Area of Science:

• Materials Science and Engineering
• Optoelectronics
• Nanotechnology

Background:

• Germanium (Ge)-based optical sources are crucial for integrated photonics.
• Effective thermal management and strain engineering are critical challenges in Ge photonics.
• Existing methods often struggle to simultaneously address heat dissipation and precise strain control.

Purpose of the Study:

• To propose and experimentally validate a novel Ge-dielectric-metal stacking approach.
• To demonstrate the dual functionality of thermal management and tensile strain engineering.
• To enhance the performance of Ge-based optical sources.

Main Methods:

• Fabrication of Ge microdisks utilizing a dielectric layer for strain and a metal layer for heat sinking.
• Experimental comparison of optical responses and temperature changes in microdisks with different pedestal materials (Al vs. SiO2).
• Finite element modeling (FEM) to simulate and validate temperature rise under optical pumping.

Main Results:

• The Ge-dielectric-metal stack significantly improved thermal management, reducing microdisk temperature rise.
• A temperature increase of only 16 K was observed with an Aluminum (Al) heat sink, compared to 200 K with a Silicon Dioxide (SiO2) pedestal under 9 mW continuous wave optical pumping.
• Experimental results showed excellent agreement with FEM simulations of thermal behavior.

Conclusions:

• The proposed stacking scheme effectively combines efficient heat sinking with controlled tensile strain.
• This approach is highly promising for developing high-performance Ge-based optical sources.
• The integration of metal and dielectric layers offers a viable solution for thermal management challenges in integrated photonics.