Studies On The Preparation And Doping Properties Of P-type Transparent Conductive Oxide Film

With the development of science and technology,the performance of TCO film is more and more demanding.p-type TCO can't combine with n-type TCO because of its low conductivity and low visible light transmission,so limits the applications of the p-type TCO applications.Therefore,how to improve the optoelectronic performance of p-type TCO has attracted the researcher's attention.Delafossite oxide is a popular material for p_type TCO.As one of the delafossite oxide,CuCrO2 possess good p-type conductivity and visible light transmission,and has a suitable lattice for hole stransport.Nevertheless,there is high possibility to improve the optoelectronic properties by impurity doping for CuCrO2 materials.Therefore,in the current work,we get the CuCrO2 delafossite film via RF magnetron sputtering and the subsequent rapid annealing process.The microstructures of the film are characterized by XRD,SEM and EDS,etc.The optical properties of the film are characterized by the spectroscopic photometer.The roles of Ni impurity induced to the CuCrO2 film are discussed.In general,this work provides an effective way to prepare a p-type TCO film with excellent performance.1.Cu-Cr-O films are prepared by RF magnetron sputtering.During this process,Cu and Cr reacted with O2,and then are deposited on the quartz substrates.After that,the films are annealed at 973 K to 1373 K for 300 s in vacuum.The as-deposition film is amorphous.After being annealed at 973 K,the film changes to the mixture of CuCr2O4 and CuO.The CuCrO2 delafossite with a mixed surface morphology of large bulk particles and small polygons is obtained via 1073 K annealing.The transmittance and electrical properties of 1373 K-annealed film decrease significantly,and the surface morphology changes from large particles to small particles accordingly,Cu crystalline grain is measured after 1373 K anealing,indicating that CuCrO2 decomposed and Cu precipitated at this annealing temperature.The Hall coefficients of the films are positive,which means that the main carriers of the films are holes.The lowest resistivity,the highest carrier concentration and mobility are found in the film annealed at 1073 K,which are 2.2?·cm,2.23 ×1018 cm3 and 1.28 cm2.V-1·s-1,respectively.The direct band gap of 3.13 eV and the light transmittance of 70%are obtained for the films with the thickness of?150 nm.After bending with plus or minus 180 degrees,the resistivity of film varies within 15%.After being stored in ambient conditions for 12 weeks,the resistivity varies within 0.005%.2.The best preparation process of Ni-doped CuCrO2 film is 10%doping concentration and 973 K-annealing temperature.The film has a conductivity of 3.176 S/cm,with an average visible light transmission of 69%.This means that the conductivity of the Ni-doped film is nearly 7 times higher than that of the intrinsic CuCrO2 film with little loss of light transmission.In CuCrO2,the maximum concentration of Ni doping is 15%to 20%,and the predominant role induced by the Ni impurity is described below:firstly,in the disordered Cu-Cr-O-Ni system,which is accquied by annealing between room temperature and target temperature,Ni atoms act as nucleators to reduce phase change resistance and critical-shaped nuclear thresholds of the system.When the CuCrO2 phase is formed,the Ni atom replaces the Cr atom as doped atoms.After the anealing temperature rises to make the CuCrO2 decompose,the Ni atom reappears in the film as a nucleator to promote the Cu-shaped nucleus.