Preparation Technology Optimazation And Porperties Of P-CuCrO₂ Thin Films Prepared By Magnetron Sputtering

Delafossite-CuCrO2 is a p-type transparent oxide semiconductor. It has high transparency and conductivity in the visible range. The CuCrO2 thin films can be applied to photoelectronics material, such as:TFT switch, solar cells, flat panel display, ozone sensor and so on. The holes in CuCrO2 mainly derive from the interstitial oxygen, copper and chromium vacancies. Compared with the n-type transparent oxide semiconductors, the conductivity of p-CuCrO2 films were lower about 3-4 orders of magnitude. Therefore, how to improve the performance of p-CuCrO2 thin films is an important problem that we need to solve. In this dissertation, p-type CuCrO2 film was prepared by RF magnetron sputtering method on the quartz glass substrate and the p-CuCrO2/n-ZnO p-n junction was successfully prepared on the silicon substrate. The effects of the substrate temperature, sputtering power and annealing time on the structure and optical properties of CuCrO2 films and Ⅰ-Ⅴ performance of p-CuCrO2/n-ZnO p-n junction were investigated by XRD, filed emission scanning electron microscope, ultraviolet-visible spectrophotometer and Ⅰ-Ⅴ performance tester. The main results were as follow:1) Under certain condition that the oxygen argon ratio was 1:4, the sputtering pressure was 2.0Pa, the sputtering power was 120W, the sputtering time was 90min and the annealing temperature was 800℃, the CuCrO2 films prepared with different substrate temperature were 3R delafossite structure. With the increase of the substrate temperature, the preferred orientation of the CuCrO2 thin film transferred from (006) to (012) plane, the light transmission properties of CuCrO2 thin films increase, and the optical band gap of the films becomes lager. The absorption edge of the films moves toward the short wavelength.2) Under certain condition that the oxygen argon ratio was 1:4, the sputtering pressure was 2.0Pa, substrate temperature was 500℃, the sputtering time was 90min and the annealing temperature was 800 ℃, the CuCrO2 films prepared with different sputtering power were 3R delafossite structure. With the increase of the sputtering power, the (012) diffraction peak of CuCrO2 films becomes more and more obvious, the films becomes smoother, the transmittance of the films increases, the optical band gap of the films becomes larger and the absorption edge of the films moves toward the short wavelength.3) Under certain condition that the oxygen argon ratio was 1:4, the sputtering pressure was 2.0Pa, substrate temperature was 500℃, the sputtering power was 120W, the sputtering time was 90min and the annealing temperature was 800 ℃, the CuCrO2 films were prepared by different annealing time. After annealing, the films are crystalline, and have 3R delafossite structure. When the annealing time increased, the (012) primary diffraction peak is gradually enhanced, the crystallization performance of the thin films was gradually increased, the pore defects are reduced, the films become smoother and the absorption edge of the films moves toward the short wavelength.4) In summary, the optimal process conditions for the preparation of CuCrO2 thin films are:the oxygen argon ratio was 1:4, the sputtering pressure was 2.0Pa, substrate temperature was 500℃, the sputtering power was 120W, the sputtering time was 90min, the annealing temperature was 800℃ and the annealing time was 5h. CuCrO2 films prepared by the optimal process that the maximum transmittance in the visible range is 77.5% and the optical band gap is 3.07eV.5) The p-CuCrO2/n-ZnO p-n junction was successfully prepared by deposition of the p-CuCrO2 films and n-ZnO films on the intrinsic silicon and p-type silicon substrates. The CuCrO2 films prepared on different substrates have 3R delafossite structure and the n-ZnO films are pure phase. By comparison, the films of the p-CuCrO2/n-ZnO p-n junction prepared on the p-type silicon have less pore defects and become smoother.6) The p-CuCrO2/n-ZnO p-n junctions prepared on the intrinsic silicon have larger turn-on voltage about IV. In the bias voltage of ±2.0V, absolute value of the ratio of forward current and reverse current is about 4.7) When the p-CuCrO2/n-ZnO p-n junctions prepared on the p-type silicon, the turn-on voltage becomes smaller which is about 0.5V. In the bias voltage of ±2.0V, absolute value of the ratio of forward current and reverse current is about 69, which shows that the rectifying characteristic significantly becomes better.