Low-frequency noise used as a lifetime test of LEDs
Low-frequency noise (1/f noise) has been measured in light emitting diodes (LEDs) which have been subjected to an accelerated life test by means of large forward bias current pulses. Over a large range of stress pulses the electrical and functional LED properties remain unaltered but an increase in the 1/f noise level was seen and this was correlated with the device reliability. The product `initial noise X initial rate of noise increase' correlated best with the LED lifetime.