Methods and devices for improving performance of III-nitride light emitting devices.
Current commercially-available III-nitride light-emitting diodes (LEDs) use an active region in a biased p-n junction to allow for electron and hole injection. However, since p-type gallium nitride (p-GaN) is difficult to contact electrically and has low hole concentration and mobility, p-GaN cannot be used as a current spreading layer and traditional p-contacts will add significant voltage to devices. Despite these inherent problems, all commercial light emitting devices utilize a p-contact and a material other than p-GaN for current spreading, typically transparent conducting oxides (TCO). Thus, there is a need to improve the performance of III-Nitride light-emitting devices.
Researchers at the University of California, Santa Barbara have developed methods and devices to overcome such limitations. These improvement include a III-nitride flip chip LED with a dielectric based mirror which improves light extraction and eliminates the need for a TCO or silver mirror, a high reflectivity ohmic contact to N-type gallium nitride utilizing vacuum annealed aluminum allowing for low contact resistivity and high reflectivity, and a III-Nitride tunnel junction LED with high electrostatic discharge (ESD) rating that improves the effective lateral current spreading whereby the electric field is spread evenly and dramatically increasing the peak voltage of ESD. Other improvements include the ability to create (AI, In, Ga, B)N structures, a method to fabricate high extraction efficiency thin film LEDs with tunnel junctions and substrate liftoff, and a buried tunnel junction aperture for III-nitride surface emitting lasers.
|Patent Cooperation Treaty||Published Application||WO2018035322||02/22/2018||2017-132|
Additional Patent Pending
LED, indled, indfeat, Flip chip, tunnel junction, III-nitride devices, surface emitting lasers