Geometric Control of Strain and Optical Properties in III-Nitride Nanostructures

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This project is jointly funded by the Electronic and Photonic Materials (EPM) Program in the Division of Materials Research (DMR) and by the Electronics, Photonics, and Magnetic Devices (EPMD) Program in the Division of Electrical, Communications and Cyber Systems (ECCS).Non-Technical Description: Semiconductors made of group-III elements in the period table and nitrogen are important materials that have applications in high-power electronics and ultraviolet and visible light emitting devices used in defense and consumer systems. Engineering of electronic and optical properties of III-nitride nanostructures via strain, the topic of this research project, is expected to improve performance, reduce power consumption, and potentially lead to new system design concepts such as ultracompact light-weight devices for efficient lighting, portable or wearable displays, and biomedical imaging systems. The project increases public awareness of energy efficient and toxin-free lighting and display technologies, and translates research findings to industry via various education and outreach activities including student training, graduate and undergraduate curriculum development, and, technology transfer and start-up activities.Technical Description: The scientific objective of this project is to establish the relationship between strain, both symmetric and asymmetric, and optical properties in III-nitride nanostructures, more specifically, the InGaN nanodisk structures. The research combines both experimental and theoretical approaches. Various InGaN nanodisk structures exhibiting different indium compositions, active region thicknesses, dimensions, and shapes are synthesized and characterized for both structural and optical properties. The specific research tasks are: (1) to establish an experimentally validated model relating the strain to the radiative properties including emission wavelength, oscillator strength, and polarization; (2) to explore the role of higher energy states on the polarization properties of light emission in InGaN nanodisks; and (3) to extend the results to other related nitride semiconductor heterostructures..