April 3rd news, according to the journal reference: The efficiency of GaN LEDs is reduced at high drive currents, and the debate about the origin of this decline has continued, and photocurrent measurements have brought it a turn.
   It is estimated that the carrier generated by the excitation of the InGaN quantum well resonant light limits the LED so that it does not have this particular layer structure. But Fred Schubert and his partners from RPI showed that these light-excited carriers can leak out of the trap, even when these structures are unbiased.
   This discovery casts a shadow over the early experimental study of LED decline. The Schubert group previously announced that electron leakage was the cause of the decline. They suspected that in an InGaN/GaN heterostructure, the resonant light excitation of the InGaN layer contained therein could not cause carriers to escape, as demonstrated by experiments. Philips Lumileds made the same conjecture, claiming that optical experiments revealed that the Auger-type compound caused a decline.
   RPI's current view is that their experiments can't decide which one is the cause of the decline. Does Auger Recombination still load escape?
   This photocurrent experiment used a 300 × 300 μm device containing a conventional InGaN/GaN multiple quantum well and an electron blocking layer. When pumped with a 405 nm light source, these 406 nm LEDs produce significant photocurrent under fully biased conditions, with a zero bias device photocurrent exceeding 15 μA at excitation power of 1 mW.
   Some LED group researchers believe that different samples are the root cause of the different origins of decline; in order to solve this problem, RPI began to investigate these samples from other manufacturers, Fred's son Martin Schubert said, "We measure all samples in Carrier escape under resonant excitation."
   Now the group intends to revisit the early work, including the comparison between external quantum efficiency and photoluminescence efficiency. Martin Schubert explained, "We will also look forward to other experiments and further study what LEDs are doing under bias conditions." ("Compound Semiconductor")
Cable Management,cable organizer,wire management,cable cover wall
NINGBO UONICORE ELECTRONICS CO., LTD , https://www.uonicore.com