Ultrawide Bandgap Hetero-structures: Growth, Characterization, and Modeling
Abstract
This research targets a material system that addresses the need for a developing and understanding ultrawide bandgap oxide heterostructures that have the potential for significant technological impact to society. Because of their unique properties, these materials have potential advantages over conventional wide bandgap semiconductors for high power electronics, deep ultraviolet sensors and detectors and even transparent conducting oxides applications. The bandgap of this oxide system can be tuned by creating of alloys with other group III elements. However, the stability of the crystal structures during thin film growth depends on the alloy composition and to some extent the growth technique. In addition the development of a p-type wide bandgap oxide combined with the n-type alloys of ยง-Ga2O3 would open up the application space to include efficient UV optoelectronics. The proposed research represents a detailed investigation involving growth and characterization of thin film heterostructures that is a high risk/high reward effort to develop an understanding for technology applications based on the engineering of the wide bandgap in oxide materials. This proposal is motivated by the need for a comprehensive study on the properties of ultrawide bandgap oxide alloys and heterostructures. The experimental effort on the epitaxial growth will include a number of deposition technique and is complemented by a suite of state-of-the-art electrical and optical characterization techniques to determine film properties and atomic simulations and modelling. In particular, the stability of the crystal structure of the various alloys and heterointerfaces will be determined to explain the results from detailed characterization of the grown films. Experiments using in-situ x-ray photoelectron spectroscopy (XPS) technique to measure the oxidation states of the cations and the band-offsets at heterointerfaces will also be used to correlate the electrical and structural properties of the various thin films and used to generate a model to accurately predict device performance. Molecular beam epitaxy will be used to grow the wide band (AlInGa)2O3 alloys using a compound sesquioxide Ga2O3 source with In and Al to produce the required composition for the monoclinic phase. A plasma source will provide the necessary activated oxygen to ensure stoichiometric films. A growth process will be developed for heterostructures with the growth and the interface probed using in-situ XPS to determine atomic intermixing and band alignments. Additional techniques including pulsed laser deposition will be employed to investigate material properties and p-type NiO growth. Heterostructures will be designed and fully characterized and probed for transport properties. Additionally, a pathway will be developed to fabricate a p-n junction using p-type NiO and an n-type (AlInGa)2O3 alloy layer. Finally a FET and a UV sensor will fabricated and tested.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 20, 2020
- Source ID
- W911NF2010298
Entities
People
- Ravi Droopad
Organizations
- Army Contracting Command
- Office of the Secretary of Defense
- Texas State University