| Transparent Conductive Oxide(TCO)materials are widely used in liquid crystal displays,solar cells,photocatalysis,thermoelectric sensing and other related technologies because of their excellent optoelectronic properties.With the continuous progress of science and technology,the performance requirements of TCO thin film materials are getting higher and higher.At present,the research reports on TCO materials mainly focus on n-type,while p-type TCO cannot match with n-type TCO materials to meet their market demand due to their low electrical conductivity and low transmission rate in visible wavelengths.Therefore,the development of p-type TCO materials with excellent optoelectronic properties has become a hot topic for researchers.P-type CuCrO2 is a promising p-type TCO material due to its unique crystal structure,good intrinsic hole conductivity and visible wavelength transmittance.In this paper,CuCrO2 films with pure phase delafossite structure were prepared by RF magnetron sputtering process combined with rapid annealing treatment at room temperature.Based on the determination of the optimum annealing temperature,we doped the intrinsic CuCrO2 films with Ni ions to improve the material properties and explored the effect of Ni ion doping on the overall properties and crystallization temperature of the CuCrO2 films.The main work results include the following two points:(1)In the preparation of intrinsic CuCrO2 thin films,it was found that the films obtained by RF magnetron sputtering deposition at room temperature were amorphous,and a small amount of CuCr2O4 phase existed in the films after annealing treatment at 700℃.CuCrO2 with CuCrO2 structure was obtained under annealing conditions of 750℃ and 800℃.The CuCrO2 structure was obtained under the annealing conditions of 750℃ and 800℃.With the gradual increase of the annealing temperature,the peak intensity of the(0 1 2)and(0 0 6)characteristic peaks of CuCrO2 also began to increase,the FWHM of the peaks decreased,and the grain size of the films increased.The CuCrO2 thin film sample obtained under annealing conditions at 800℃ has a transmittance of 48%in the visible range and an optical band gap of 3.12 eV.The material exhibits p-type conductivity,with a conductivity of 0.106 S·cm-1 and good electrical stability,and the change in conductivity of the film is controlled within 1.03%after being placed in air at room temperature for 8 weeks.(2)On the basis of the preparation of intrinsic CuCrO2 films,we prepared Ni ion-doped CuCr1-xNixO2(x=5,10,15,20%)thin film materials.ni ions were effectively doped into the crystal structure of CuCrO2,the films did not contain other heterogeneous phases,exhibited good c-axis selective growth,and the characteristic diffraction peaks of CuCrO2 were not shifted.The films are most crystalline at 15%doping.The SEM results show that the CuCr1-xNixO2(x=0,5,10,15,20%)films are composed of nano-sized rod-shaped particles with uniform distribution,the surface of the material is flat and smooth,and the size variation of the film grains tends to increase and then decrease with increasing doping concentration.The EDS results further confirmed that the composition ratio of each element in the films was in accordance with our requirements.The band gap width of the film also decreases with increasing doping content,which may be caused by the appearance of band-tailed states due to doping.The electrical properties of the films were tested,and the CuCr1-xNixO2(x=0,5,10,15,20%)films all exhibited p-type conductivity,and the conductivity of the films showed a multiplicative increase with increasing Ni ion doping content,with CuCr0.85Ni0.15O2 reaching 0.659 S-cm-1 at room temperature,and exhibiting good electrical stability.When overdoped,the crystallinity of the films is destroyed and the defect centers increase,leading to a decrease in carrier mobility and a decrease in the electrical properties of the films.When analyzing the XRD patterns of CuCr1-xNixO2(x=0,5,10,15,20%)films after annealing at 700℃,it was found that the CuCrO2 phase appeared prematurely in the material when the Ni doping content reached 15%and 20%,indicating that a certain degree of Ni doping lowered the crystallization temperature of CuCrO2,and through DSC test analysis we believe that the Ni doping We believe that this is caused by the Ni doping which introduces lattice distortion and thus facilitates atomic migration and mass transfer,resulting in a lower onset temperature for the CuCr2O4 chemotaxis to CuCrO2 reaction.In conclusion,Ni ion doping can effectively enhance the electrical properties of the films while maintaining the transparency of the films almost unchanged,thus improving their application potential. |
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