Multianalyte Mg-Doped InGaZnO Electrolyte-Insulator-Semiconductor Biosensors and Multiple Material Characterizations of Membrane Nanostructures

Mg-doped InGaZnO (IGZO) electrolyte-insulator-semiconductor (EIS) biosensors were fabricated with multianalyte sensing capability. H
⁺
, Na
⁺
, and K
⁺
ion sensing behaviors were examined and urea, glucose, and creatine detection through enzymatic reaction was performed. Results indicate that Mg doping IGZO membranes with appropriate annealing had better multi-sensing performance than that of regular membranes. Moreover, multiple material characterizations of membrane nanostructures, including of atomic force microscopy (AFM) surface morphology evaluation, scanning electron microscopy (SEM), and transmission electron microscopy (TEM), and selected area electron diffraction (SAED) were conducted. Material crystalline and chemical binding properties were also performed, including energy dispersive X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDX), and photoluminescence (PL). These detailed studies indicate that the incorporation of Mg in the membrane can form MgO crystals to enhance compactness, crystallization and grainization, which can reinforce the surface sites on the membrane. Mg-doped IGZO EIS multianalyte biosensors show promise for future portable and wearable biosensing applications.