Growth And Its Lithium Storage Properties Of Doped Zno Thin Films

This paper mainly researched the fabrication methods of two kinds of doping ZnO thin films, and the influence in crystal structure and electrochemical properties induced by impurity.Research areas included the following 2 items,(1) The fabrication methods of 4 kinds of ZnO1-xSx films with different ratios, followed by the research and analysis in their crystal structure, electrochemical properties. We employed pulsed laser deposition technology to successfully fabricate a series of ZnO1-xSx films with different doping ratios. Instead of a simple combination of ZnO and ZnS, ZnO1-xSx is an independent single crystal phase. ZnO1-xSx (0.1<x<0.9) has a smaller band gap than ZnO and ZnS, therefore it's expected having a better conductivity. Our research results indicated that: in all the 4 ratios, ZnO0.28S0.72 had the best reversible cyclic performance than others. Our research also indicated: for double-anion compound ZnO1-xSx, after discharging(reducing) into independent Zn, Li2O and Li2S phases, single phase ZnO1-xSx can be reformed again durning reverse charging(oxidating), not a combination of ZnO and ZnS.(2) The fabrication methods of 7 kinds of Al doped ZnO (AZO) thin films with different ratios, followed by the research and analysis in their physical, electrochemical properties. First of all, we used RF magnetron sputtering to fabricate a series of AZO thin films with 7 different ratios, we researched their crystal structure, electrical and optical properties influenced by 2 parameters (doping ratios and distance between target- substrate). The results showed: impurity Al will cause the variation in ZnO structure's lattice constant, the lowest resistivity of 4.94×10-4Ω·cm was got in 2% doping ratio, and we found properly decrease in distance can help improving carrier concentration and mobility. Secondly, we did some electrochemical detection in AZO/Li system, the result showed:the high conductivity induced by 1%-3% Al doping can effectively improve the reversible reaction capacity. However, excessive doping will produce independent inactive Al2O3 crystal, which caused the increase of resistivity, so the reversible oxidation/reduction reaction will be blocked.The idea of the overall research paper is:doping some impurity(anion S2- and cation Al+) into the ZnO thin films, to improve ZnO films'conductivity through changing the bang gap and increasing carrier concentration, and ensuring the high transmittance (in visible range) of ZnO. Then, these improved doping ZnO films were applied in Lithium battery as electrodes, we will observe the improvement in reversible cyclic capacity.