Ga2O3 nanorod-based extended-gate field-effect transistors for pH sensing

• Published in: Materials science & engineering. B, Solid-state materials for advanced technology Vol. 276; p. 115542
• Main Authors: Chiang, Jung-Lung, Shang, Yi-Guo, Yadlapalli, Bharath Kumar, Yu, Fei-Peng, Wuu, Dong-Sing
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.02.2022; Elsevier BV
• Subjects: Biosensors; Chemical bath deposition; Crystal lattices; Extended-gate field-effect transistor; Field effect transistors; Fourier transforms; Ga2O3 nanorods; Gallium oxides; Infrared spectroscopy; Lattice vibration; Microscopy; Nanorods; pH sensitivity; Semiconductor devices; Transmission electron microscopy; Chemical bath deposition; Extended-gate field-effect transistor; Ga2O3 nanorods; pH sensitivity
• ISSN: 0921-5107; 1873-4944
• DOI: 10.1016/j.mseb.2021.115542

In this study, the pH-sensing characteristics of gallium oxide (Ga2O3) nanorods based on an extended-gate field-effect transistor were grown on the ITO/glass via chemical bath deposition. Ga2O3 nanorods were observed using scanning electron microscopy, X-ray diffraction, energy-dispersive spectrometry, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and Raman spectrum instruments. The experimental results showed that the α-Ga2O3 nanorods had several crystalline orientations ([104], [110], [024], [116]) after being annealed at 400–600 °C for 1 h. The FTIR and Raman spectrum measurements confirmed the existence of Ga−O and Ga−OH bending modes. As observed by the TEM, the nanorods had a good crystal quality and atomic lattice arrangement. In addition, the Ga2O3/ITO pH sensor possessed high pH sensitivity (51.59–64.29 mV/pH), good linearity (98.5%–99.8%), and long-term stability (drift, 2.75 mV/h; pH = 7). Overall, the α-Ga2O3 could be used as a low-cost FET-based manufacturing sensor for pH or biosensors.