High-performance quantum cascade lasers at λ ∼ 9 µm grown by MOCVD

Area of Science:

• Semiconductor Optoelectronics
• Quantum Cascade Lasers
• Mid-Infrared Photonics

Background:

• Quantum Cascade Lasers (QCLs) are crucial semiconductor devices for generating coherent light in the mid-infrared spectrum.
• Achieving high power output and stable operation at room temperature remains a key challenge for QCL development.
• Indium Phosphide (InP)-based materials offer advantages for high-performance optoelectronic devices.

Purpose of the Study:

• To demonstrate a high-power Indium Phosphide (InP)-based Quantum Cascade Laser (QCL) operating around 9 µm.
• To investigate the temperature stability and performance characteristics of the fabricated QCL.
• To optimize the active region design for enhanced electroluminescence properties.

Main Methods:

• Fabrication of a 4-mm-long, 10.5-µm-wide ridge InP-based QCL using metalorganic chemical vapor deposition (MOCVD).
• Incorporation of a high-reflection (HR) coating on the laser cavity.
• Design of the active region utilizing a dual-upper-state (DAU) and multiple-lower-state (MS) configuration.

Main Results:

• Achieved maximum pulsed peak power of 1.55 W and continuous-wave (CW) output power of 1.02 W at 293 K.
• Demonstrated a low pulsed threshold current density of 1.52 kA/cm².
• Observed a wide electroluminescence (EL) spectrum with a full-width at half maximum (FWHM) of 466 cm⁻¹.
• Exhibited high characteristic temperature coefficients: T₀ = 228 K and T₁ = 680 K over a temperature range of 293 K to 353 K.

Conclusions:

• The developed InP-based QCL exhibits high output power and excellent temperature stability, suitable for various mid-infrared applications.
• The DAU/MS active region design contributes to a broad emission spectrum and robust device performance.
• MOCVD growth is confirmed as an effective method for producing high-performance, high-power QCLs with enhanced thermal characteristics.