Polarization-Doped InGaN LEDs and Laser Diodes for Broad Temperature Range Operation

Area of Science:

• Semiconductor Physics
• Optoelectronics
• Materials Science

Background:

• Indium Gallium Nitride (InGaN) based light emitters are crucial for optoelectronic applications.
• Broad temperature range operation is a significant challenge for InGaN devices.
• Polarization doping offers a potential route to enhance device performance.

Purpose of the Study:

• To investigate the stable, continuous-wave operation of polarization-doped InGaN light emitters over an extended temperature range.
• To identify and analyze the limiting factors for efficient light emission in LEDs and laser diodes at various temperatures.

Main Methods:

• Fabrication of InGaN light-emitting diodes (LEDs) and laser diodes utilizing composition-graded AlGaN for p-type layers.
• Incorporation of thin Mg-doped GaN subcontact layers and AlGaN electron blocking layers.
• Continuous wave (CW) operation testing across a broad temperature spectrum (20 K to 295 K).

Main Results:

• Efficient emission achieved in InGaN LEDs from 20 K to 295 K and in laser diodes from 77 K to 295 K.
• Electron overshooting identified as a limiting factor for LED efficiency at low temperatures.
• Freeze-out of the Mg-doped electron blocking layer limits laser diode performance below 160 K.

Conclusions:

• Polarization-doped InGaN light emitters can achieve stable operation over a remarkably broad temperature range.
• The GaN:Mg subcontact layer demonstrates satisfactory performance even at cryogenic temperatures (20 K).
• Understanding temperature-dependent limitations is key to further optimizing InGaN optoelectronic devices.