A1-doped Zno Thin Films And Laser Induced Voltage Effect

Zinc Oxide (ZnO) is aⅡ-Ⅵsemiconductor material with direct wide band-gap, which has hexagonal wurtzite structure. Because of the surface (002) has lowest energy, crystal have preferred orientation of axial C. Transparent conducting Al doped ZnO thin films have been recently gained much attention due to their good photoelectric behaviors and studied as photoelectron information materials also. These thin films were prepared by Pulsed Laser Deposition and Laser-Induced Voltage effect (LIV) was discovered on Zn1-xAlxO thin films grown on vicinal-cut single crystalline substrates for the first time, which dependence on different substrate temperature, deposition oxygen pressure, annealing oxygen pressure, Al doping level were investigated.Al doped ZnO ceramics were prepared by solid state reaction method used as the targets for depositing thin films. These targets, characterized with X-ray diffraction (XRD), showed wurzite structure. The resistance of the targets were measured by standard four-point probe method, the results showed that a series of Al doped Zn1-xAlxO targets are semiconductor behavior, and when Al doping level x=1at %, then the target has resistivity minimum.The epitaxial Zn1-xAlxO thin films of wurzite structure were prepared by pulsed laser deposition (PLD) on single crystalline sapphire and silicon substrates. The lattice parameters and crystalline quality of Zn1-xAlxO thin films dependence on different substrate temperature, deposition oxygen pressure, annealing oxygen pressure and Al doping level were investigated.A series of Al doped Zn1-xAlxO thin films were measured by a single theta scans and then the rocking curves were obtained. The results proved that a good symmetry with all the rocking curves of the Zn1-xAlxO thin films. With the concentration of doing Al atoms increasing, the FWHM of the rocking curve increases.The relationship between resistance and temperature of Zn1-xAlxO thin films on single crystalline sapphire and silicon substrates under different preparation process. As a result, with the temperature decreasing, the resistance of the Zn1-xAlxO thin films grown on p-type silicon substrates have been changed from semiconductor to conductor behavior when the concentration of doing Al atoms increasing from x=0.5at% to x=1.5at%, but when the concentration of x=2at% and 3at%, the conductor behavior with the Zn1_xAlxO thin films. The conductor behavior with the Zn1-xAlxO thin films grown on sapphire substrates when substrate temperature was 800℃, but when substrate temperature was 400℃, the semiconductor behavior with it.The preparation process under different measurement of laser induced voltage Zn1-xAlxO film, and analyzes the signal of the signal LIV wide, rise and decline along time. The time that the preparation technology for the minimum time of Zn1-xAlxO film in high sensitivity were obtained, It is helpful to application with device that high-sensitivity and fast response.