UCSB's new discovery sparked a LED decline

The quantum efficiency is reduced under high drive current, and UCSB has joined the LED drop problem. UCSB's influential solid-state lighting and display center researchers said, it is "electronic spillover" produced this phenomenon.

International nitride semiconductor research group Kenneth Vampola explained that the team has prepared a variety of standard Blu ray LED structure. They are characterized by the fact that a single quantum well in the p region can emit shorter wavelengths of light, and so does the standard multi quantum well (MQW). These work under the forward bias of LED, which is emitted from the MQW active layer and single quantum well. Some electrons pass through the active layer and the undoped electronic barrier, and then release a photon with the hole in the p region of the device.

Although a single quantum well will certainly emit light, Vampola still can not calculate the proportion of electrons to reach this part of the chip. Interestingly, just before the quantum efficiency of the LED began to drop, the quantum wells began to emit photons. Vampola said the electronic spillover from electronic disclosure, the reasons for the decline of this is the Rensselaer Polytechnic Institute Fred Schubert team; however, he also believes that the reason is: the theory of freezing hole is Vampola's colleague Hisashi Masui proposed. LED manufacturer Philips Lumileds suspected auger complex is the reason for the decline, Vampola said it could not rule out this possibility.

Mike Krames is the head of the Lumileds research team on the decline, he pointed out that commercial LED in the electronic barrier layer is often doped with other elements, which proves the discovery of Vampola. According to Krames, adding a doping process in the electronic barrier of the UCSB device may prevent the electron from overflowing.

Source: LED chip network