Iman Roqan builds spectroscopy lab in Saudi Arabia
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BEYOND THE LAB
Iman Roqan builds spectroscopy lab in Saudi Arabia Prachi Patel
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he King Abdullah University of Science and Technology (KAUST) sits on a sprawling desert campus 80 kilometers north of the port city of Jeddah in Saudi Arabia. The graduatelevel research university has a multibillion-dollar endowment and a lofty mission: build a force of graduates with globally competitive technical expertise in order to diversify the country’s economy beyond petroleum. Iman Roqan, an assistant professor of materials science and engineering, is proud to be part of KAUST’s mission. Roqan, a petite woman with a determined look who chooses to wear her abaya and headscarf despite the University’s liberal policies, is one of five female faculty members at the university out of a total of nearly 90, and the only Saudi woman. She is busy setting up her state-ofthe-art laboratory, the first one in the country devoted to the spectroscopic studies of semiconductors. Her curiosity and interest in semiconductor spectroscopy has driven her academic progress over the years. As a PhD student in physics at the University of Strathclyde in Scotland, Roqan investigated the optical and structural properties of group-III nitride semiconductors—indium nitride, gallium nitride, and aluminum nitride— which are used for high-intensity lightemitting diodes (LEDs). Her goal is to improve the quality of grown films of these materials, so they can lead to more efficient solar cells and LEDs. High-efficiency solar cells could have large implications for her country, Roqan said. Saudi Arabia, which holds one-fifth of the world’s crude oil reserves, currently meets nearly all of its energy needs from fossil fuels. The country plans to spend $100 billion to venture out into so-
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lar and nuclear power to meet increasing energy demands with a more sustainable mix of sources. “Solar cells will be very important for Saudi Arabia,” Roqan said. “Solar power is the second biggest topic of interest for energy after oil.” One of Roqan’s projects focuses on indium gallium nitride (InGaN). The material is used in today’s blue and green LEDs, but scientists started exploring it for solar cells in 2003. “You can engineer the bandgap of indium gallium nitride to cover a large range and can capture the entire solar spectrum from near-UV to infrared,” Roqan said. “So far, silicon-based solar cells have shown better light-to-electricity conversion efficiency, but this material was proven theoretically to be much more efficient.” The theoretical limit for the conversion efficiency of silicon solar cells is 29%. With InGaN, it could be possible to grow multiple layers with different bandgaps and make cells that are over 50% efficient. However, growing high-quality films has proven difficult, and scientists have made devices that are 3% efficient at best. The problem is that indium atoms tend to form clusters when the material is
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grown with high indium content. In a solar cell, electrons and po
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