A paper written by Taha Ayari, a Ph.D. student in the Georgia Tech School of Electrical and Computer Engineering (ECE), was ranked 39th among the 3,000 cited papers in the Nature Publishing Group journal Scientific Reports.
The paper, entitled “Gas sensors boosted by two-dimensional h-BN enabled transfer on thin substrate foils: towards wearable and portable applications,” was published in the November 9, 2017 issue.
Ayari is based at Georgia Tech-Lorraine (GTL). His coauthors are his Ph.D. advisor Abdallah Ougazzaden, GTL director and an ECE professor; Chris Bishop of the Institut Lafayette; Matthew Jordan, Suresh Sundaram, Xin Li, Saiful Alam, Youssef ElGmili, and Jean Paul Salvestrini, all of the CNRS Unité Mixte Internationale 2958 Laboratory; Gilles Patriarche of CNRS - Centre de Nanosciences et Nanotechnologies; and Paul Voss, an ECE associate professor based at GTL.
The transfer of GaN-based gas sensors to foreign substrates provides a pathway to enhance sensor performance, lower the cost, and extend the applications to wearable, mobile, or disposable systems. The main keys to unlocking this pathway is to grow and fabricate the sensors on a large h-BN surface and to transfer them to the flexible substrate without any degradation of the performances.
In this work, Ayari and his colleagues developed a new generation of AlGaN/GaN gas sensors with boosted performances on a low cost flexible substrate. They fabricated two-inch wafer scale AlGaN/GaN gas sensors on sacrificial two-dimensional (2D) nano-layered h-BN without any delamination or cracks and subsequently transfer sensors to an acrylic surface on metallic foil. This technique resulted in a modification of relevant device properties, leading to a doubling of the sensitivity to NO2 gas and a response time that is more than six times faster than before transfer. This new approach for GaN-based sensor design opens new avenues for sensor improvement via transfer to more suitable substrates, and is promising for next-generation wearable and portable opto-electronic devices.