Researchers at the Georgia Institute of Technology developed a transfer technique to facilitate the production of low-cost wearable, portable and disposable sensing devices meant to be used for environmental applications.
The researchers produced sensors in which ammonia can be detected at parts-per-billion levels and differentiate between nitrogen-containing gases. This process begins with monolayers of boron nitride grown on two-inch sapphire wafer using an MOVPE (metal organic vapor phase epitaxy) process. The nitride surface coating is very thin and produces crystalline structures that have strong planar surface connections but week vertical connections.
“Mechanically, we just peel the devices off the substrate, like peeling the layers of an onion,” explained Abdallah Ougazzaden, director of Georgia Tech-Lorraine in Metz, France and a professor in Georgia Tech’s School of Electrical and Computer Engineering. “We can put the layer on another support that could be flexible, metallic or plastic. This technique really opens up a lot of opportunity for new functionality, new devices – and commercializing them.”
The goal is to allow high performance gallium nitride gas sensors to be grown on sapphire substrates and then transferred to metallic or flexible polymer support materials. These then would be made into the wearable, mobile and disposable sensing devices. As explained in the paper, published in the November 9, 2017 issue of Scientific Reports, “this approach for engineering GaN-based sensors is a key step in the pathway towards economically viable, flexible sensors with improved performances that could be integrated into wearable applications.”
In the future, the Georgia Tech researchers hope to boost the quality of the devices, one team members says, “one of the challenges ahead is to improve the quality of the materials so we can extend this to other applications that are very sensitive to the substrates, such as high-performance electronics.”
To learn more about this project, click here.