Preparation And Photoelectric Properties Of Copper Oxide Films

Cuprous oxide(Cu₂O) is a p-type semiconductor.The cuprous oxide crust is rich and nontoxic,with a direct band gap of 2.17 e V.It has a good match with the visible light range of the solar spectrum,and the theoretical energy conversion efficiency can reach 20%.Its intrinsic p-type conductivity and high solar absorption efficiency make it a great prospect in photocatalysis and photovoltaic applications.However,the application of cuprous oxide is limited due to its poor electrical properties.It is reported in the literature that nitrogen doping can significantly improve the electrical properties of cuprous oxide.In this paper,nitrogen-doped cuprous oxide films were prepared by magnetron sputtering.The nitrogen doping and different preparation parameters for cuprous oxide films were studied.XRD,SEM,XPS,Raman spectrum,absorption spectrum and hall analysis were used to study the influence of nitrogen doping concentration and different preparation parameters on the composition,structure,morphology,photoelectric properties of cuprous oxide films.The change of nitrogen doping state in Cu₂O and its influence on the photoelectric properties were explored with the increase of nitrogen doping concentration.The results show that increasing the growth temperature can improve the crystal quality and increase the grain size of the film.The carrier concentration decreases and the mobility and resistivity increase.Annealing significantly improves the crystalline quality of the grains.Increasing the annealing temperature,the grains gradually become larger,the grain boundary density is relatively reduced,the scattering of carriers is weakened,the mobility is increased,and the carrier concentration is significantly reduced.The threshold value of sputtering power is 45W,and the increase of sputtering power accelerates the deposition rate and the grain gap.The higher the matching degree between the substrate crystal plane and the sputtered film crystal plane,the better the film performance.The doping mode of N in p-type N-doped cuprous oxide thin films are N_O and(N₂)_Cu.As the nitrogen doping concentration increases,the proportion of N_O decreases and the proportion of(N₂)_Cu increases.The increase of doping concentration shows the transition process of Cu₂O(111)?Cu₂O(111)/Cu₂O(200)?Cu₂O(111).The optical band gap expanded significantly after N-doping,from 2.17ev to about 2.45ev.The doping of N has a significant improvement in the electrical properties of Cu₂O.A high quality N-doped cuprous oxide film with carrier concentration of 1.10×10¹⁸cm^-3,mobility of 1.6cm ²/vs,and resistivity of 3.6?cm was obtained at 75 sccm Ar,3 sccm O₂ and 7.1%(6 sccm)N₂.