Study on the carbon nanotube separative structure for the extended gate H+-ion sensitive field effect transistor

We use the carbon nanotube (CNT) as the material of the pH sensing layer of the separative structure for the extended gate H+-ion sensitive field effect transistor (EGFET) device. The CNT paste was prepared with CNT powder, Ag powder, silicagel, the di-n-butyl phthalate and the toluene solvents by appropriate ratio, then immobilized on the silicon substrate to form the carbon nanotube sensing layer. We measured the I-DS-V-G curves of the carbon nanotube separative structure EGFET device in the different pH buffer solutions by the Keithley 236 I-V measurement system. According to the experimental results, we can obtain the pH sensitivities of the carbon nanotube separative structure EGFET device, which is 62.54mV/pH from pH1 to pH13.