Anisotropic Etching of CVD Grown Graphene for Ammonia Sensing

• Published in: IEEE sensors journal Vol. 22; no. 5; pp. 3888 - 3895
• Main Authors: Yagmurcukardes, Nesli, Bayram, Abdullah, Aydin, Hasan, Yagmurcukardes, Mehmet, Acikbas, Yaser, Peeters, Francois M., Celebi, Cem
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.03.2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Ammonia; anisotropic etching; Chemical vapor deposition; Density functional theory; Etching; Fluid flow; gas sensors; Graphene; High resistance; Humidity; hydrogen etching; Microscopy; Optical microscopy; Optical properties; QCM; Quartz crystals; Raman spectroscopy; Room temperature; Sensitivity; Sensors; Substrates; Water chemistry
• ISSN: 1530-437X; 1558-1748
• DOI: 10.1109/JSEN.2022.3146220

Bare chemical vapor deposition (CVD) grown graphene (GRP) was anisotropically etched with various etching parameters. The morphological and structural characterizations were carried out by optical microscopy and the vibrational properties substrates were obtained by Raman spectroscopy. The ammonia adsorption and desorption behavior of graphene-based sensors were recorded via quartz crystal microbalance (QCM) measurements at room temperature. The etched samples for ambient NH 3 exhibited nearly 35% improvement and showed high resistance to humidity molecules when compared to bare graphene. Besides exhibiting promising sensitivity to NH 3 molecules, the etched graphene-based sensors were less affected by humidity. The experimental results were collaborated by Density Functional Theory (DFT) calculations and it was shown that while water molecules fragmented into H and O, NH 3 interacts weakly with EGPR2 sample which reveals the enhanced sensing ability of EGPR2. Apparently, it would be more suitable to use EGRP2 in sensing applications due to its sensitivity to NH 3 molecules, its stability, and its resistance to H 2 O molecules in humid ambient.