Enhancing the deep ultraviolet response of 4H-silicon carbide-based photodiodes between 210 nm and 255 nm

This work demonstrates two novel 4H-SiC-based photodiode structures that enhance the response from ~200 nm to 260 nm by increasing the absorption of DUV photons within the high-electric-field depletion region and more efficiently collecting photo-generated carriers through drift as opposed to diffusion, despite the presence of surface recombination. In particular, the two devices discussed in this work have replaced the heavily doped, top-illuminated, n⁺-layer of conventional p-n^--n⁺ diodes by a semi-transparent metal contact to create a p-n^--metal based device and by an n-type, wider bandgap AlGaN layer to create a heterojunction 4H-SiC/AlGaN p-n^--n⁺ based device.