Fiscal Year 2011 Director's Strategic Initiative Final Report
Heterogeneous Device Architectures Incorporating Nitride Semiconductors for Enhanced Functionality of Optoelectronic Devices

Report No. ARL-TR-6870
Authors: Anand V. Sampath, Meredith L. Reed, Michael Gerhold, and Michael Wraback
Date/Pages: March 2014; 42 pages
Abstract: Heterogeneous devices combine dissimilar materials with complementary device functionalities to achieve new functionalities that may provide revolutionary advances in technology. In these novel devices the physics and engineering of the interface of the dissimilar materials plays a critical role and requires considerable research. While nitride semiconductors have had great success as materials for sources and detectors of electromagnetic radiation across the spectrum from the ultraviolet (UV) to terahertz, heterogeneous integration of these materials with others having different spontaneous polarization, different crystal structure or a new functionality hold promise for devices with improved performance. This report discusses research efforts on two representative examples, III-Nitride/silicon carbide (SiC) avalanche photodetectors and compositionally inhomogeneous indium gallium nitride (InGaN) terahertz sources. Specifically, we demonstrate the efficacy of using III-Nitride semiconductors to improve the quantum efficiency (QE) of a photodetector employing a SiC-based gain region over a wide spectral range from 240 to 365 nm by overcoming surface states and weak absorption that limit the QE of homogenous SiC-based photodetectors in the deep UV and near UV regions, respectively. Furthermore, we have observed enhanced terahertz generation due to large internal in-plane electric fields in heteroepitaxially grown semi-polar and nonpolar GaN thin films due to the presence of self-assembled zincblende inclusions in an otherwise wurtzite crystal structure.
Distribution: Approved for public release
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Last Update / Reviewed: March 1, 2014