“…The bandgap of ZnO has been tailored and the oxygen concentration is varied by doping with different metal ions such as tin (Sn), cobalt (Co), copper (Cu), nickel (Ni), manganese (Mn), magnesium (Mg), etc., to improve various physical properties [ 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 ]. Doping, therefore, provides a practical way to tune physical properties, particularly optical, electrical, magnetic, charge transport, and electrochemical properties to meet specific requirements [ 37 , 38 , 39 , 40 , 41 , 42 ]. Besides this, doping also influences the crystal size, surface potential, semiconductor energy levels, and carrier concentration that are utilized for sensors [ 9 , 43 ].…”