Quantitative and depth-resolved deep level defect distributions in InGaN/GaN light emitting diodes.

Area of Science:

• Materials Science
• Semiconductor Physics
• Optoelectronics

Background:

• Deep level defects in semiconductor devices can significantly degrade performance.
• Understanding defect origins in Indium Gallium Nitride/Gallium Nitride (InGaN/GaN) multi-quantum wells (MQWs) is crucial for efficient light-emitting diodes (LEDs).

Purpose of the Study:

• To investigate and distinguish defect states within the InGaN quantum well and GaN quantum barrier regions of InGaN/GaN LEDs.
• To determine the depth-dependent concentration of these defects.
• To explore the physical origins and impact of these defects on LED performance.

Main Methods:

• Bias-dependent steady-state photocapacitance.
• Deep level optical spectroscopy.
• Capacitance-voltage (C-V) measurements with nanoscale depth profiling.

Main Results:

• Distinct defect states in InGaN quantum wells and GaN quantum barriers were identified.
• Deep level concentrations exhibited strong variations with depth within the MQW region.
• Evidence suggests evolving defect incorporation mechanisms during the MQW growth process.

Conclusions:

• The depth-dependent nature of defects highlights the sensitivity of the MQW growth process.
• Understanding these variations is key to optimizing InGaN/GaN LED fabrication and performance.
• Further research into defect incorporation mechanisms can lead to improved LED efficiency and reliability.