Heterogeneously integrated InGaN-based green microdisk light-emitters on Si (100).

Area of Science:

• Materials Science
• Optoelectronics
• Semiconductor Physics

Background:

• Heterogeneous integration of nitrides on silicon is crucial for advanced photonics and information processing.
• Developing robust methods for transferring GaN epilayers onto Si substrates is essential for realizing these applications.

Purpose of the Study:

• To demonstrate a feasible method for transferring GaN epitaxial layers onto Si (100) substrates.
• To fabricate and characterize optoelectronic devices, specifically microcavities, on this integrated platform.
• To investigate the impact of stress mitigation on device performance.

Main Methods:

• GaN epilayer grown on patterned sapphire substrate transferred to Si (100) using wafer bonding, laser lift-off, and chemical mechanical polishing (CMP).
• Uniform thinning of GaN epilayer to 800 nm with low surface roughness (2.33 Å RMS).
• Fabrication of microcavities and characterization of optically and electrically injected devices.

Main Results:

• Successful transfer and thinning of GaN epilayer on Si with significantly reduced residual stress (79.4% mitigation) and improved surface quality.
• Achieved optically-pumped green lasing at ~505.8 nm with a narrow linewidth (~0.48 nm) from ~12 µm microdisks.
• Demonstrated electrically injected microdisks with a low turn-on voltage (~2.0 V) and minimal leakage current (~2.4 pA at -5 V).

Conclusions:

• The developed heterogeneous integration technique provides a viable pathway for large-area optoelectronic devices based on nitrides.
• The stress mitigation and improved material quality are critical for achieving efficient lasing and device operation.
• This platform is compatible with traditional semiconductor processing, paving the way for integrated photonic and electronic systems.