Abstract
Many studies have been conducted on membranes implemented as pH sensors for measuring pH sensitivity; nevertheless, the effect of metal oxide semiconductor field effect transistors was not taken into account. Hence, this study was conducted to measure the sensitivity of the CuS membrane with and without a field effect transistor. The CuS membrane was deposited onto a glass substrate using the spray pyrolysis technique. The sensitivity and linearity in the absence of the field effect transistor were measured to be 22.86 mV/pH and 95.62%, whereas the presence of the field effect showed slightly higher sensitivity and linearity of 24 mV/pH and 98.18%, respectively. The CuS membrane synthesized in the presence of the field effect transistor also showed higher stability because the metal oxide semiconductor was not immersed in a buffer solution. Furthermore, the hysteresis of the CuS membrane, measured for 5 min, yielded a value of 12.8 mV. The structural characteristics of the membrane confirmed the formation of a single, pure CuS phase, whereas the morphological characteristics showed porous agglomerations of square nanocrystals.