| AVS 66th International Symposium & Exhibition | |
| Electronic Materials and Photonics Division | Tuesday Sessions |
| Session EM+OX+TF-TuA |
| Session: | Nikolaus Dietz Memorial Session: Wide and Ultra-wide Band Gap Materials and Devices |
| Presenter: | Vincent Woods, Pacific Northwest National Laboratory |
| Authors: | V. Woods, Pacific Northwest National Laboratory L. Hubbard, Pacific Northwest National Laboratory Z. Sitar, North Carolina State University A.Y. Kozhanov, Georgia State University |
| Correspondent: | Click to Email |
This energetic talk will focus primarily on the development of advanced nitride-based avalanche photodiode devices but will also highlight the many contributions that Nikolaus Dietz made to the field of real-time optical characterization, materials development and advanced growth techniques. Iterative development and advances in growth techniques and characterization have allowed sufficient improvement in materials quality to show demonstrable g ain in Avalanche Photodiode Detector (APD) device structures currently being produced for nuclear detection applications. This contribution will present the structural and optoelectronic properties of GaN/AlGaN heterostructures grown by Metal Organic Chemical Vapor Deposition (MOCVD) on AlN, GaN and sapphire templates/substrates. The target parameters for the materials heterostructures have been modeled for utilization in APD structures operating in the UV region. Optical modeling has improved absorption within the heterojunction as well as maximized light trapping within the device. Electronic modeling has determined the optimal dopant concentrations for maximum impact ionization rate, as well as tolerance to defects and unintentional doping. This application required advances in the defect densities, surface morphology, and interfaces. Surface morphological and structural properties of the GaN/AlGaN heterostructures are analyzed by Atomic Force Microscopy (AFM), and high resolution transmission electron microscopy (TEM). Recent results related to the gain of the final APD device will be presented.