Carrier transport mechanisms of InGaN-based light-emitting diodes using a single pulsed current

Abstract

The current-voltage characteristics of InGaN-based light-emitting diodes (LEDs) with various In compositions are analyzed. The emission spectra and ideality factors of ultraviolet, violet, and blue LEDs are investigated in a single pulsed current mode. A comparison of the emission spectra shows that with an increase in the current density, diffusion, recombination, and tunneling dominate the carrier transport mechanism, and a correlation exists between the carrier transport mechanisms and the broadening of the emission spectrum. However, the increase in defect-related emissions and the blue shift of the emission peak are more noticeable with an increase in the current density in In-rich blue LEDs. Theoretical modeling revealed that the carrier density increases drastically when the current density is above a certain threshold. The increase in carrier density in the quantum well causes a growth of the carrier tunneling, recombination, diffusion, and overflow due to which the ideality factor and efficiency decrease.