Nitride Based Ultraviolet LED with an Ultraviolet Transparent Contact

In conventional UVLED nitride devices, a metal mirror is often used as an electrical contact and requires the incorporation of other metals in order to obtain a low resistance electrical contact with the semiconductor material. These additional metals, however, are not transparent to emitted photons which causes a significant decrease in device efficiency. Although dielectric mirrors provide a potential alternative, their poor electrical properties are not suitable for high efficiency devices.

Researchers at the University of California, Santa Barbara have developed a nitride based UVLED with an ultraviolet transparent contact (UVTC) that is an alloy composition of (Ga, Al, In, B)O semiconductors, such as Ga₂O₃. The n-type, p-type and UVTC regions are all transparent to UV light and minimize internal reflections within the UVLED by eliminating mirrors and/or mirrored surfaces. As a result, the UVLED output is drastically increased via the minimization of light re-absorption. Therefore, the improved light emission efficiency of UVLEDs enables the expansion of ultraviolet semiconductor device applications into a variety of commercial products.