Hydrothermally synthesized Al-doped β-Ga2O3 microrods for enhanced pH sensing performance

• Published in: Journal of solid state chemistry Vol. 339; p. 124934
• Main Authors: Yadlapalli, Bharath Kumar, Chou, Hsin-Yu, Singh, Anoop Kumar, Chiang, Jung-Lung, Wuu, Dong-Sing
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.11.2024
• Subjects: Al-doped β-Ga2O3/FTO; Hydrothermal deposition; pH sensitivity; Hydrothermal deposition; pH sensitivity; Al-doped β-Ga2O3/FTO
• ISSN: 0022-4596
• DOI: 10.1016/j.jssc.2024.124934

In our study, Al-doped β-Ga2O3 microrods were deposited on FTO glass substrate via hydrothermal method followed by calcination at 700 °C for 3 h. The Al-doped β-Ga2O3 microrods were characterized using XRD, SEM, XPS, and FTIR spectroscopy techniques. The intrinsic β-Ga2O3 extended-gate field-effect transistor (EGFET)-based pH sensor exhibited a pH sensitivity of 57.29 mV/pH with 99.34 % linearity within the pH range of 3–11. Conversely, the Al-doped β-Ga2O3 EGFET-pH sensor, containing 0.52 at. % of Al, demonstrated an elevated pH sensitivity of 77.63 mV/pH with 99.17 % linearity. Our findings indicate that the incorporation of Al enhances the pH sensing capabilities of β-Ga2O3 microrods to the presence of additional binding sites facilitated by its improved specific surface area. Remarkably, even a minute amount (0.52 at. %) of Al doping in β-Ga2O3 suffices to significantly improve the performance of pH sensing. These results underscore the potential of Al-doped β-Ga2O3 as a promising material for development of high-performance ion or biosensors. Al-doped α-GaOOH was deposited onto commercially available fluorine-doped tin oxide (FTO) glass substrates using the hydrothermal method. The annealed samples align with the monoclinic β-Ga2O3 phase. Al-doped β-Ga2O3 EGFET-pH sensor, containing 0.52 at. % of Al, demonstrated an elevated pH sensitivity of 77.63 mV/pH with 99.17 % linearity. This process is shown schematically in the graphical abstract. [Display omitted] •Al-doped β-Ga2O3 particles were successfully deposited on FTO by hydrothermal method.•Al-doped β-Ga2O3 micro rods based EGFET pH sensor is fabricated.•The pH sensitivity of Al-doped β-Ga2O3 microrods was investigated for varying Al doping concentrations (0 mM/L to 6 mM/L).•The Al-doped β-Ga2O3 pH sensor exhibited higher pH sensitivity compared to intrinsic β-Ga2O3 microrods.