480 nm InGaN-based cyan laser diode grown on Si by interface engineering of active region

Area of Science:

• Semiconductor Physics
• Materials Science
• Optoelectronics

Background:

• Indium Gallium Nitride (InGaN)-based laser diodes (LDs) grown on silicon (Si) are essential for advanced applications like laser displays and lighting.
• Achieving long-wavelength LDs on Si requires precise interface engineering of high-indium-content InGaN multi-quantum wells (MQWs) to mitigate scattering and absorption losses.

Purpose of the Study:

• To improve the interface quality and crystalline structure of InGaN active regions in InGaN-based LDs grown on Si.
• To enable the development of long-wavelength InGaN-based LDs on Si for expanded applications.

Main Methods:

• Utilized a graded-compositional InGaN lower waveguide (LWG) capped with a 10-nm-thick Aluminum Gallium Nitride (AlGaN) layer for interface engineering.
• Characterized the morphology and crystalline quality of the InGaN active region, focusing on V-pit density and root-mean-square surface roughness.

Main Results:

• Achieved significantly improved morphology and sharp interfaces in the InGaN active region.
• Reduced V-pit density by one order of magnitude (from 4.8 × 10^8 to 3.6 × 10^7 cm⁻²).
• Decreased root-mean-square surface roughness from 0.3 nm to 0.1 nm.

Conclusions:

• Successfully demonstrated a room-temperature, electrically injected 480 nm InGaN-based cyan LD grown on Si.
• Achieved a threshold current density of 18.3 kA/cm² under pulsed current operation, indicating successful interface engineering and improved device performance.