NEWS
NORMAN, Okla. – Sarah Sharif, a researcher with the University of Oklahoma, has been awarded funding from the U.S. Department of Defense (DoD) to create innovative light detectors that pick up mid-wave and long-wave infrared signals at higher temperatures than previously considered achievable. Through this research, Sharif’s team could set the foundation for advancements in sensory technology ranging from night vision to aerospace navigation.
Avalanche photodetectors (APDs) are powerful devices that can identify and measure even faint traces of light, including infrared light not visible to the human eye. However, APDs have traditionally been created using semiconductor materials such as silicon and indium. Those 3D materials produce electric signals at room temperature that can interfere with the photodetectors’ infrared sensitivity, requiring them to operate in lower, cryogenic temperatures.
Sharif, who is an assistant professor in OU’s Gallogly College of Engineering, aims to solve this dilemma by developing APDs with ultra-thin 2D materials: substances such as black phosphorous and graphene that measure only an atom deep. Because they produce fewer electric signals, APDs using them may be able to detect mid- and long-wave infrared light at higher temperatures. These photodetectors could then be made smaller and less expensive, further increasing how widely their infrared capabilities can be applied.
“Nobody has discovered an avalanche photodetector based on 2D material that works this way, which was key in my proposal,” Sharif said. “For the first time, we’re proposing one that's going to work at room temperature.”
Her project team is among more than two dozen groups – four of which are led by OU researchers – to earn funding through the DoD’s Defense Established Program to Stimulate Competitive Research (DEPSCoR) 2024 Research Collaboration competition. DEPSCoR aims to strengthen higher education research infrastructure in underutilized U.S. states and territories. Through the competition, projects are awarded in areas associated with DoD initiatives.
Sharif noted that 2D materials are extremely thin compared to existing 3D material used for APDs. 3D materials are measured in micrometers, the same measurement used for human hair width, while 2D materials are measured in nanometers. For scale, one nanometer is a thousand times smaller than a micrometer.
But the materials’ atomic-level depth also means they are extremely susceptible to environmental damage. To protect them, Sharif’s team is developing photodetector structures that combine the ultra-thin 2D materials with bulkier 3D materials, layering them together like a microscopic multi-tier sandwich. “However, this also requires perfect interfaces,” she said. “Otherwise, leakage, recombination and noise rapidly increase.”
Sharif said that this design structure aims to improve APD efficiency, making them faster at sensing infrared light. These enhanced photodetectors, with their smaller, lower-cost qualities, could be applied across military, environmental and aerospace systems. Early research results have been promising, Sharif said, and she expects to file a patent for these APDs.
The grant not only funds important research but also strengthens other university goals. Sharif is an affiliate faculty member of the Dodge Family College of Arts and Sciences’ Center for Quantum Research and Technology (CQRT) and noted that advanced APDs could transform the center’s quantum-optics work. “This award also enables interdisciplinary student training in materials, photonics and electronic technologies,” she said.
Sharif’s team includes doctoral students at the INQUIRE Lab and Joseph Tischler, an associate professor at the College of Arts and Sciences and CRQT member who is a collaborator with the project. She is also leading more research proposals that are in the works.
“We are trying to position Oklahoma as a competitive contributor to defense-related research and technology manufacturing,” Sharif said. “We hope to create pathways for high-tech workforce development, including graduate training and job creation, and support local companies through new collaboration opportunities.”
About the University of Oklahoma
Founded in 1890, the University of Oklahoma is a public research university located in Norman, Oklahoma. As the state’s flagship university, OU serves the educational, cultural, economic and health care needs of the state, region and nation. For more information about the university, visit www.ou.edu.
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Sarah Sharif, a researcher with the University of Oklahoma, has been awarded funding from the U.S. Department of Defense (DoD) to create innovative light detectors that pick up mid-wave and long-wave infrared signals at higher temperatures than previously considered achievable.
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