STUDY ON ISFET WITH 2D HEXAGONAL-BORON NITRIDE AS SENSING FILM FOR PH SENSING APPLICATION

Abstract

This thesis focuses on study of pH sensitivity and drift of h-BN sensing film in ISFETs. The EGISFET with h-BN sensing film shows a pH sensitivity of 1-5 mV/pH and low drift value of ~0.50 mV/h. This proves high potential of using h-BN as a pH inert material in REFET. The effect of Al₂O₃ layer thickness on pH sensing performance of Al₂O₃/h-BN sensing film is then studied. The devices with 5 nm Al₂O₃ coated h-BN sensing film show pH sensitivities of larger than 50 mV/pH while at the same time exhibiting lower drift values than those with Al₂O₃ single sensing film. Finally, the EGISFETs with 2D MoS2 FET and Al₂O₃/h-BN sensing film were fabricated and studied in both single- and dual-gate configuration. The dual-gate configuration further improves the pH sensitivity to 166 V/pH. All these demonstrate high promising potentials of using h-BN in ISFETs for pH sensing applications.