Investigation of pulsed laser-deposited Al2O3 as a high pH-sensitive layerfor 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 s ensors (LAPS). Al2O3 has been reported to be better in pH sensitivity and l ong-term drift of the sensitivity over Si3N4 in ISFET-based biosensors. In this work the possibility of using pulsed laser-deposited Al2O3 as pH-sensi tive layer for the LAPS instruments is presented. Initially an average pi-I -sensitivity of above 57 mV/pH has been observed. After a couple of weeks t he sensitivity reduces to about 56.3 mV/pH. The observed sensitivity agrees with the reported sensitivity in ISFET-based sensor devices. The sensor re sponse has been found quite linear with the pH value. The pH sensitivity wa s 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 pa-se nsitive layer for LAPS-based biosensors. (C) 2000 Elsevier Science B.V. All rights reserved.