Studies On Preparation Of Transparent Oxide Semiconductor Films And Their Photoelectric Properties

The ZnO:Ga and NiO:Cu target materials were prepared by means of the solid state reaction method using ZnO, Ga₂O₃, NiO and CuO powders as their raw materials. The influence of different sintering temperatures on the density and the doping ratio of the ZnO:Ga and NiO:Cu ceramic target material was studied. The ZnO:Ga and NiO:Cu transparent semiconducting films with highly c axis preferred orientation were deposited on glass substrates by using radio frequency （RF） magnetron sputtering coating machine, respectively. The effects of the sputtering power, argon gas flow, sputtering pressure, substrate temperature, argon and oxygen ratio on the microstructure and the photoelectric properties of the ZnO:Ga and NiO:Cu films were investigated, respectively. Under the optimum film deposition condition, the ZnO:Ga and NiO:Cu multilayer films were deposited on the ITO glass substrate by using radio frequency （RF） magnetron sputtering coating machine. And the I-V characteristic curves of the ZnO:Ga and NiO:Cu multilayer films were tested. The main experimental results were listed as following:（1） ZnO:Ga ceramic target material with a doping ratio of Ga atom to Zn atom of 4.34%, and with a density as high as 98.84% can be prepared by sintering at 1500 ℃ for 4 hours.（2） NiO:Cu ceramic target material with a doping ratio of Ni atom to Zn atom of 9.96%, and with a density as high as 98.02% can be prepared by sintering at 1300 ℃ for 4 hours.（3） As the sintering temperature higher than 1550 ℃, the density of the ZnO:Ga ceramic target material decreased to 96%, while the doping ratio of Ga atom to Zn atom increased to 18.67%. And the doping ratio of Ga atom to Zn atom increases with the sintering time.（4） As the sintering temperature higher than 1100℃ during the sintering process, the NiO:Cu ceramic target material will be cracked and bended if the heating rate is higher than 1 ℃/min.（5） The Hall Effect experimental results show that all the ZnO: Ga films prepared in this work are n-type semiconductors. XRD measurement results indicate that there is only a characteristic peak of ZnO （002） in the XRD patterns of the ZnO:Ga films.（6） The grain size and the carrier mobility of the ZnO:Ga film increase with the sputtering power, while the resistivity and the optical transmission rate of the film decrease with the increase of the sputtering power. The experimental results show that the optical transmission rate of the ZnO:Ga films are higher than 80%.（7） The grain size, the carrier mobility and the resistivity of the ZnO:Ga films vary with the argon flows, the sputtering pressures, the substrate temperatures and the ratio of O2/Ar during the deposition process.The grain size of the ZnO:Ga film is relatively large, the carrier mobility of the film is relatively high, and the resistivity of the film is relatively low when the argon flow is 60 SCCM. And the optical transmission rate of the ZnO:Ga film is relatively high when the argon flow is 80 SCCM.The grain size of the ZnO:Ga film is relatively large, the carrier mobility of the film is relatively high, and the resistivity of the film is relatively low when the sputtering pressure is 0.35Pa during the deposition process. And the optical transmission rate of the ZnO:Ga film is relatively high when the sputtering pressure is 2Pa.The grain size of the ZnO:Ga film is relatively large, the carrier mobility of the film is relatively high, and the resistivity of the film is relatively low when the substrate temperatures is 450℃ during the deposition process. And t the optical transmission rate of the ZnO:Ga film is relatively high when the substrate temperatures is 350℃.The grain size of the ZnO:Ga film is relatively small, and the transmittance of the ZnO:Ga film is relatively high when the ratio of O2/Ar is 1:1.（8） The Hall Effect experimental results show that all the NiO: Cu films prepared in this work are p-type semiconductors.（9） The carrier mobility, the resistivity and the optical transmission rate of the NiO:Cu films vary with the sputtering power, the sputtering pressures, the substrate temperatures and the ratio of O2/Ar during the deposition process.The resistivity and carrier mobility of the NiO:Cu film increases with the sputtering power; while the optical transmission rate of the NiO:Cu film decreassd with the increase of the sputtering power.XRD measurement results indicate that the characteristic peak of NiO （111） in the XRD patterns of the NiO:Cu film with a relatively high intensity when the substrate temperatures is 350℃, while the intensity of this peak decreases with the further increase of the substrate temperatures. The resistivity and carrier mobility of the NiO:Cu film will increase first and then decrease with the increase of the substrate temperatures. And the optical transmission rate of the NiO:Cu film increase with the substrate temperatures.The characteristic peak of NiO （111） in the XRD patterns of the NiO:Cu film with a relatively high intensity when the ratio of O2/Ar is 1:1 during the deposition process. As the ratio of O2/Ar increasing, the resistivity of the film decreases first and then increases, whiles the carrier mobility of the film increases first and then decreases. And the optical transmission rate of the NiO:Cu film increases with the ratio of O2/Ar.（10） The pn junction was prepared by deposited a p-type NiO:Cu film on a n-type ZnO:Ga film. And the typical I-V curve of the pn junction can be obtained by the means of a Hall Effect instrument.