Modulation behaviors of surface plasmon coupled light-emitting diode

Area of Science:

• Optoelectronics
• Materials Science
• Semiconductor Devices

Background:

• Light-emitting diodes (LEDs) are crucial optoelectronic devices.
• Modulation bandwidth determines the speed of LED operation.
• Surface plasmon (SP) coupling is a technique to enhance light-matter interactions.

Purpose of the Study:

• To compare modulation bandwidths of LEDs with and without SP coupling.
• To investigate the effect of SP coupling on LED performance across different mesa sizes and current densities.
• To analyze the factors limiting the modulation bandwidth enhancement by SP coupling.

Main Methods:

• Fabrication of LEDs with varying square-mesa sizes (60-300 micron).
• Integration of Ag nanoparticles and GaZnO dielectric interlayer for SP coupling.
• Measurement of modulation bandwidths and photoluminescence decay rates.
• Analysis of RC time constants (resistance and capacitance).

Main Results:

• SP coupling enhanced modulation bandwidth by 44-48% for LEDs.
• Enhancement was independent of LED mesa size and injected current density (139-1667 A/cm²).
• Observed enhancement ratios were lower than predicted by photoluminescence decay rates due to increased RC time constants.

Conclusions:

• SP coupling is an effective method to boost LED modulation bandwidth.
• Increased device resistance, due to SP coupling materials, limits the full potential enhancement.
• Further optimization of SP coupling integration is needed to overcome RC limitations.