Title: Origin of Operating Voltage Increase in InGaN-based Light-emitting Diodes under High Injection: Phase Space Filling Effect on Forward Voltage Characteristics,
Abstract: As an attempt to further elucidate the operating voltage increase in
InGaN-based light-emitting diodes (LEDs), the radiative and nonradiative
current components are separately analyzed in combination with the Shockley
diode equation. Through the analyses, we have shown that the increase in
operating voltage is caused by phase space filling effect in high injection. We
have also shown that the classical Shockley diode equation is insufficient to
comprehensively explain the I-V curve of the LED devices since the transport
and recombination characteristics of respective current components are
basically different. Hence, we have proposed a modified Shockley equation
suitable for modern LED devices. Our analysis gives a new insight on the cause
of the wall-plug-efficiency drop influenced by such factors as the efficiency
droop and the high operating voltage in InGaN LEDs.