| AVS 64th International Symposium & Exhibition | |
| Electronic Materials and Photonics Division | Monday Sessions |
| Session EM-MoA |
| Session: | Novel Materials and Devices for Electronics |
| Presenter: | Vincent Woods, Pacific Northwest National Laboratory |
| Authors: | V. Woods, Pacific Northwest National Laboratory L. Hubbard, Pacific Northwest National Laboratory L. Campbell, Pacific Northwest National Laboratory N. Dietz, Georgia State University Z. Sitar, North Carolina State University |
| Correspondent: | Click to Email |
Group III-N avalanche photodiodes (APD) offer tailorable UV sensitivity and selectivity not currently available for scintillated light detectors. Materials growth challenges continue to hamper the development and implementation of UV III-N detectors. This presentation details the efforts at Pacific Northwest National Laboratory in collaboration with North Carolina State University and Georgia State University to develop device structures and fabrication processes Group III-N APDs. The focus of these efforts is to produce nitride photomultiplier (NPM) devices similar to a silicon photomultiplier (SiPM). Compared to traditional photomultiplier tubes (PMTs), the NPMs can be smaller, more rugged, consume less power than PMTs, and have lower dark currents than SiPMs for UV light detection.
The large bandgap of III-N systems allows for UV photo-detection that is solar blind resistant to ambient stray light. Unlike silicon, the bandgap and associated dark current in the III-N system can be tuned by changing the composition of the AlxGa1-xN materials system. A direct advantage of the III-N APDs over SiPMs and PMTs is the matching of the device (by matching the band gap) to a scintillator.
Conventional radiation detection relies on the use of dyes to wavelength shift the scintillated light to match the PMT or SiPM. Tailoring the APD to the scintillator allows for increased resolution of scintillated light without broadening/attenuation from dye interactions. A tailorable APD also allows for exploration of scintillating materials which cannot be dye matched to a SiPM or PMT. The tailorable III-N system opens up new avenues in radiation detection. Research into the selection of appropriate scintillator materials and compositional requirements of the Nitride-based APD structures will be presented. In addition to the materials characterization, optoelectronic modeling aimed towards efficient APD operation will be shown.
The progress in the growth of nitride heterostructures in both Al-rich and Ga-rich AlGaN materials systems will be presented along with detailed materials characterization. This project is developing the materials capability to tailor III-N APDs to match scintillated light. The development of materials knowledge and capability will enable tailorable III-N APDs for direct matching to UV scintillated light, a significant improvement over current technology.