This Materials World Network project, involves investigators from Arizona State University and the University of Michigan in the US, the University of Victoria and Simon Fraser University in Canada, the University of Surrey in the UK, and Philipps-Universität in Germany, and focuses on a relatively unexplored family of III-V semiconductor alloys containing the heaviest naturally occurring group V element, bismuth. Bismuth is non-toxic, relatively inexpensive, and the heaviest non-radioactive element in the periodic table. Furthermore, Bi-alloys have a very large spin orbit splitting and a smaller temperature dependence of the bandgap when compared with conventional semiconductor alloys.
The research objective of this international collaboration is to theoretically and experimentally develop study III-V bismide compound semiconductors for IR and mid IR optoelectronic devices and other small bandgap devices at the readily available lattice constants of GaAs, InP, InAs, and GaSb. The research activities include molecular beam epitaxy growth of III-V bismide materials; structural characterization and property measurements aimed at developing an understanding of dopant incorporation, bandgap energy, band offsets, materials performance, and radiative efficiency of these materials and related devices; and theoretical analysis of the electronic and optical properties of quantum-well structures and optical devices based on Bi-containing compound semiconductors. The theoretical and device-level research will be performed mainly by the overseas scientists. The networking objective of this project is to link this Materials World Network with the larger global scientific research community by hosting two international workshops, one at the University of Michigan during the summer of 2010 and one at the University of Surrey during the summer of 2011, and by developing cyberinfrastructure to enhance data sharing and analysis between Bi-alloy investigators and the broader scientific community. These activities, promote sample exchange and tool sharing for the development of III-V bismide materials, enhance science and technology through broader dissemination, understanding, and face-to-face interactions between students and researchers, and advance data sharing and information exchange, which may well inspire further innovation and change the way data is managed and material challenges are addressed.
Overview: This project theoretically and experimentally explored and developed bismuth containing III-V semiconductor systems with narrow bandgaps for mid and far infrared device applications. Semimetallic GaBi and InBi are alloyed with semiconducting GaAs and InAs to develop an innovative class of small bandgap III-V semiconductors that cover the technological important atmospheric infrared transmission window. Intellectual Merit: This project advances knowledge by alloying bismuth with arsenic on the group-V sublattice to develop materials in the technological important 8-12 micron atmospheric transmission window. These alloys have significant and highly exploitable electrical and optical properties beyond those of conventional III-V semiconductors where arsenic is alloyed with antimony. Specifically, a window, in terms of growth temperature and group V flux, is identified for the molecular beam epitaxy growth of high quality InAsBi lattice matched to GaSb. Broader Impacts: This project benefits society by advancing the materials knowledge base of III-V bismides to enable novel devices needed for present and future engineering grand challenges, such as i) mid and long infrared lasers and detectors for homeland security and pollution detection, ii) efficient infrared lasers and detectors for information and communication technology, and iii) photovoltaic and thermal photovoltaic solar-electrics for sustainable energy conversion. This activity advanced discovery and understanding while promoting teaching, training, and learning by i) connecting innovative and fundamental materials research and education, ii) bringing together researchers and students with broad areas of expertise to understand and discover how the addition of bismuth to narrow gap III-V semiconductors impacts band structure, bandgap, band offsets, and material performance; and iii) providing data management and examination to guide the design and engineering of III-V bismuth materials and devices over a wide range of narrow bandgap energies. The project enhanced science and technology through broad dissemination and understanding via i) face-to-face interaction at international workshops and conferences, ii) publication of student and researcher results in international journals and books, and iii) advancing data sharing and information exchange to further inspire innovative and rewarding research.
