Study on preparation process of La1.89Ce0.11CuO4-x film and junction characteristics of electron/hole superconductor heterostructure

In this work, the La1.89Ce0.11CuO4-x (LCCO) film with good superconductivity is prepared on the basis of a close study on the process of fabricating the LCCO film via pulse laser deposition (PLD). The effects of heating, atmosphere, and annealing temperatures on the structure and superconducting properties of the LCCO film are studied, obtaining the optimal process that requires a deposition substrate temperature of 700 degrees C, an oxygen pressure of 30 Pa, and an annealing deoxygenation temperature of 600 degrees C. Subsequently, the electron/hole double-layer superconducting film (LCCO/YBa2Cu3O7-delta (YBCO) bilayers) is obtained by preparing LCCO film on the YBCO film. The R-T tests show that the initial superconducting transition temperature (T-c) of the YBCO in the bilayers is about 45 K, and the T-c of the LCCO is near 16 K. The further testing of the LCCO/YBCO bilayers under ultraviolet irradiation reveals that the structure can produce salient photovoltaic phenomena. The photovoltage and photocurrent experience a jump when the films undergo superconducting transition, indicating that the potential barrier at the LCCO/YBCO interface changes. This can be attributed to the transition of the interface barrier from a PN junction type to the Schottky junction type.