Hybrid Growth Method for Improved III-Nitride Tunnel Junction Devices
Tech ID: 25976 / UC Case 2015-904-0
A commonly explored limitation of p-GaN is that it is a poor current spreading layer and that traditional p-contacts will increase operating voltages in III-nitride devices. The introduction of tunnel junctions solves these issues and expands the opportunities for new device designs. This technology seizes the opportunity increase the conductivity and efficiency of the p-GaN layer.
Researchers at UC Santa Barbara have developed a hybrid growth method for III-nitride tunnel junction devices that uses metal-organic chemical vapor deposition (MOCVD) to grow one or more light-emitting or light-absorbing structures and ammonia-assisted or plasma-assisted molecular beam epitaxy (MBE) to grow one or more tunnel junctions. Unlike p-type gallium nitride (p-GaN) grown by MOCVD, p-GaN grown by MBE is conductive as grown, which allows for its use in a tunnel junction. Moreover, the doping limits of MBE materials are higher than MOCVD materials, which allows for better tunnel junctions that reduces the operating voltage of these devices and increases their efficiency while enabling new types of device structures. These tunnel junctions can also be used to incorporate multiple active regions into a single device. In addition, n-type GaN (n-GaN) can be used as a current spreading layer on both sides of the device, relaxing the requirement for a transparent conductive oxide (TCO) layer or a silver (Au) mirror.
- Increased conductivity and efficiency of p-GaN layer
- Current spreading with GaN
- No requirement for a TCO or silver mirrors
- Simpler manufacturing process
- Reduced operating voltage
- Laser Diodes
- Solar cells
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