Improved piezoresistive properties of ZnO/SiC nanowire heterojunctions with an optimized piezoelectric nanolayer

The vital issue for semiconductor pressure sensors is how to improve the sensitivity of their piezoresistive behavior. In this work, aiming to substantially promote the sensitivity, ZnO/SiC nanowire heterojunctions with various ZnO piezoelectric shell thicknesses were constructed by adjusting the depositing times of atomic layer deposition (ALD). It was found that the thicknesses of coupled ZnO nanolayers played a profound effect on the response of the heterojunctions to the change of stresses, representing the tailored piezoresistive behaviors. Accordingly, the piezoresistive coefficient was optimized to ~ 9.47 × 10–11 Pa−1 with an enhanced ΔR/R0 value of ~ 0.88, once the ZnO nanolayer thickness is fixed at ~ 20 nm, superior to most of pressures sensors based on SiC nanomaterials. This work may provide a novel strategy for exploring advanced SiC-based pressure sensors by coupling with suitable thickness of the piezoelectric nanolayer to improve piezoresistive behaviors. The tailored piezoresistive performance of ZnO/SiC nanowire heterojunctions with a adjusted shell thicknesses of ZnO piezoelectric nanolayers was reported, which had an enhanced piezoresistive coefficient of 9.47 × 10–11 Pa−1 and a ΔR/R0 of 0.88.