Investigation of pulsed laser-deposited Al2O3 as a high pH-sensitive layer for LAPS-based biosensing applications

In this work Pulsed Laser-Deposited (PLD) Al2O3 has been investigated as an alternative high pH-sensitive layer for light-addressable potentiometric sensors (LAPS). Al2O3 has been reported to be better in pH sensitivity and long-term drift of the sensitivity over Si3N4 in ISFET-based biosensors. In this work the possibility of using pulsed laser-deposited Al2O3 as pH-sensitive layer for the LAPS instruments is presented. Initially an average pH-sensitivity of above 57 mV/pH has been observed. After a couple of weeks the sensitivity reduces to about 56.3 mV/pH. The observed sensitivity agrees with the reported sensitivity in ISFET-based sensor devices. The sensor response has been found quite linear with the pH value. The pH sensitivity was measured for several weeks and a low drift was found in the long-term use that shows the possibility of using PLD Al2O3 as the high and stable pH-sensitive layer for LAPS-based biosensors.