Ultrasonically synthesized MgZnO nanoparticles for enhanced piezo-photocatalysis and MgZnO/p-Si heterojunction diode characteristics

Limitations in practical implementations of ZnO nanomaterials could be solved by tuning the properties of ZnO via doping process. We have doped the Mg2+ ions in the ZnO nanostructures (MgZnO) via the ultrasonic synthesis procedure. The structural study revealed the shrinkage of the crystallite size of the wurtzite system for Mg2+ doping concentration. The TEM images revealed the morphological changes for Mg2+ doping from particulate (50 nm) to nanoflower structures (200 nm) in ZnO. Optical studies revealed the enhanced UV photons absorption and emission intensities for Mg doped ZnO compared to pristine ZnO. The calculated bandgap values from the absorption spectroscopy of the ZnO, MgZnO-1, MgZnO-3, and MgZnO-5 are 3.34 eV, 3.40 eV, 3.51 eV, and 3.57 eV. The prepared MgZnO/p-Si heterojunction diodes showed excellent rectification behavior and enhanced electrical properties for Mg2+ doping. The diode obtained with 5% of Mg2+ had exhibited the ideality factor value of 3.1. Pristine ZnO had exhibited only 66% of photocatalytic methylene blue (MB) degradation efficiency. One hundred percent degradation of MB had been achieved via piezo-photocatalytic effect with 5% Mg2+ doped ZnO, whereas piezocatalysis and photocatalysis had shown 82% and 98% respectively.