Kinetics of narrow-spectrum LED glow under pulsed power

The results of experimental investigations of the glow kinetics of narrow-spectrum LEDs based on InGaN-GaN 450 and 520 nm and AlGaInP-GaAs 625 nm structures are presented. The increase and decrease of the light flux intensity under pulsed power are described by exponential dependences containing fast and slow components. The time constants of both components decrease with the increase of the pulse frequency for all three types of LED samples. The time constant of the slow component decreases with the increase of the current and voltage pulse amplitudes. The maximum light output on the frequency dependences of LED energy characteristics is observed at the frequency of 75…100 kHz. Further frequency increase results in the decrease of the LED energy efficiency. The obtained results are explained based on the LED equivalent electrical and energy circuits.