Preparation And Properties Of CuAlO 2 Ceramics

Based upon the theory of the chemical modulation of the valence band, a p-type transparent conducting oxide CuAlO₂ thin films with delafossion structure were firstly prepared by Kawazoe since the end of last century. CuAlO₂ materials have attracted great interesting since they were found. It can bring the hope to make the preparation of transparent device becoming easy. So, the research of preparation and related properties of transparent conducting oxide CuAlO₂ has an important scientific significance. CuAlO₂ ceramics and the transition metal element Fe³⁺ doped in CuAlO₂ ceramics were synthesized by solid phase in this paper. The main research processes achieved have been summed up as the following two aspects.Used Cu₂O and Al2O₃ as raw materials, to prepared CuAlO₂ ceramics samples are prepared by solid-state reaction method, which are sintered at 1150 ℃、1160 ℃、1170 ℃、1180 ℃、1190 ℃ and 1200 ℃ respectively. It can be determined the lowest temperature of the prime minister is 1047 ℃ by thermal analysis tests. The experimental study show that the main component of the experimental samples is CuAlO₂. With increasing of sintering temperature, the peak intensity of CuO mixed phase will be reduced and the main phase CuAlO₂ content will be improved by XRD. It is also confirmed that the main component of the sample preparation is CuAlO₂ by Raman spectroscopy. Density test shows that increasing sintering temperature can make ceramics density decreased. SEM image shows that the grain size will be increasing slightly as the sintering temperature increasing. EDS test data shows that the atoms ratio of Cu, Al, and O is very close to the theoretical ratio. Hall effect measurement found that ceramics conductivity reached the maximum 1.782×10-3（??cm）^-1 at 1150 ℃. The sintering temperature increasing will caused the electric conductivity decreasing.The samples of CuAlO₂ ceramics doped by transition metal ion Fe³⁺ are sintered at 1150 ℃. Fe³⁺ can partly replace Al³⁺. Phase, morphology and EDS testing found that the different proportion of Fe³⁺ can be well mixed into ceramics. Ceramics density test results show that the ceramics density will increasing as the mixed proportion increasing. When the mixed rate is 0.20,the density value of ceramics reached the maximum 5.5885 g/cm³. Hall effect test show that the p-type conductive cannot be changed with Fe³⁺ doping in ceramics, and the ceramics conductivity can be improved too. When the mixed rate is 0.15,the conductivity value of ceramics can be reached the maximum 0.1729（??cm）^-1. The results of Hall effect tested at low temperature show that the donor in materials can be frozen which will make the conductivity decreasing.