| The ZnO thin film doped with ⅢA group elements is considered as a promising candidate for substituting ITO due to its merits, such as high transmittance (over90%in the visible range), outstanding electric properties (～10-4Ω·cm), innoxiousness and cheapness. In this paper, we prepared Al-and Ga-doped ZnO (AZO and GZO) transparent conductive films (TCF) by Inductively Coupled Plasma Enhanced Physical Vapor Deposition (ICP-PVD). The Structure, surface, transmittance, electrical and electric structure properties were investigated to compare the doping effect on application properties of ZnO TCF. The optical properties of GZO TCF were also studied to confirm the possible emissions and related defects.At the same time, ZnO TCF is also an attractive candidate electrode for6H-SiC based photoelectric devices due to its similar wurtzite crystal structure and relatively small lattice mismatch (3.3%along the c-axis). In this paper, we prepared Al-and Ga-doped ZnO/6H-SiC heterojunctions, and characterized their structure, interface and band structure. The preliminary application of GZO TCF-electrode on6H-SiC based photoconductive switch was also realized.The main work included:1. A serial of ZnO thin films were prepared by ICP-PVD, the suitable process parameters were confirmed. The as deposited1mol%Ga-doped ZnO thin film show a good properties, with transmittance93%and resistivity7.68×10-4Ω·cm. The effect of oxygen partial pressure (PO2) on properties of GZO thin films was also discussed. The photoluminescence of GZO films deposited under different PO2were studied by Gauss fitting. The fitting results suggest two adjacent green emissions located at2.50eV and2.65eV were attributed to donor-acceptor pair combination, corresponding to GaZnO+VZn-→GaZn++VZn2-and GaZnO+OiO→GaZn++O1-transitions, respectively. The conclusion was consistent with the low temperature photoluminescence of GZO films before and after rapid thermal annealing.2. The2mol%Ga and Al doped ZnO thin films were grown under different deposition atmospheres to discuss the transparence electric and electronic properties. With the same doping concentration and experiment process, the conductivity of AZO films were better than that of GZO, which was due to the higher hall mobility induced by smaller Al scattering radiusl. But the transparence properties was revus, which was due to the smoother surface of GZO films induced by surfactant element Ga. This results suggest the Al and Ga co-doping might be enhanced transparent conductive properties of ZnO thin film. With the same2mol%doping concentration, the doping elements both increased the band gap energy of ZnO, but GZO were0.3eV higher than that of AZO. The Synchrotron radiation photoelectron spectroscopy (SRPES) measurements sugeest the valance band of AZO were different from that of GZO. Al doping effect is different from Ga, which might enhance the2p-3d coupling in ZnO valance band, which induced a higher valance band maximum.3. Ga doped ZnO (GZO) and Al doped ZnO (AZO) thin films were deposited on n-6H-SiC to form the heteroj unction structure. The band alignments of the doped ZnO/6H-SiC heterojunctions were studied by using the synchrotron radiation photoelectron spectroscopy. Band alignments of GZO/SiC and AZO/SiC heterojunctions were determined by the band offsets calculation. AZO/SiC heterojunction has bigger band offsets than ZnO/SiC and GZO/SiC heterojunction, which is due to the closer doping element covalence radius. Ga-0is more closer to Zn-O than Al-O. The higher mismatch induces higher band offsets on heterojunction interface. The Si-and C-faced GZO/SiC were also prepared and characterized, the valance band offset difference of them was just0.05eV.4. Band alignments of GZO/SiC heterojunctions were increased after rapid thermal annealing process, be0.1eV and0.25eV for Si-and C-faced, respectively. The SRPES showed a new component was formed on heterojunctions'interface after RTA, which was deduced to be "SiO2" component. This component was deeper and with higher concentration in C-faced GZO/SiC heterojunction than that in Si-faced GZO/SiC heterojunction. The result suggests that the RTA process was not suitable for ZnO/SiC heterojunction. 5. The transmittance and resistivity of2mol%Ga doped ZnO thin films deposited on SiC substrate were96%and5.68×10-4Ω·cm, respectively. The GZO and SiC contact performance as ohmic contact, which suggests that GZO film is a suitable electrode for SiC-based opt-electric device. The SiC Photoconductive switch has been successfully fabricated with GZO thin films as front electrode, which showed an on-state performance while be excitated with lOmJ laser under500V voltage. The on-state resistance was13.2Ohm.
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