High quality nano-scaled fluorine and nitrogen co-doped anatase phase TiO2 can be obtained from the conversion of ammonium oxotrifluorotitanate by thermal treatment. The photocatalytic activity of TiO2 treated at 800oC shows the highest photocatalytic activity and is about 1.3 times of commercial P-25. The heterojunctions of ZnSe/TiO2 and ZnS/TiO2 prepared by metal organic vapor phase epitaxy shows 2.0 and 1.5 times the photocatalytic activities of commercial P-25. In this study, nano-scaled TiO2, ZnSe/TiO2 and ZnS/TiO2 heterojunctions show one to one correspondence between carrier lifetime and photocatalytic activity.

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The high Dit is the major problem of III-V compound semiconductor MOSFET, which causes the pinning of the surface Fermi level near the middle of the energy gap. The GaAs with (NH4)2Sx treatment (S-GaAs) can remove the native oxides on GaAs and prevent it from oxidizing. The electrical characteristics of fluorinated polycrystalline TiO2 films deposited on p-type(100) S-GaAs were investigated. The fluorine from liquid phase deposition solution can passivate the grain boundary of polycrystalline TiO2 prepared by MOCVD. The leakage current through the grain boundaries was suppressed. The leakage current of MOCVD-TiO2/S-GaAs can be improved from 6.8 x 10-6 and 0.2 A/cm2 to 3.41 x 10-7 and 1.13 x 10-6A/cm2 under positive and negative electric fields at 1.5 MV/cm, respectively. Dit and k can be improved from 1.44 x 1012 cm-2eV-1 to 4.6 x 1011 cm-2eV-1 and 52 to 65, respectively. The effective oxide charges can be improved from 2.5 x 1012 C/cm-2 to 9.3 x 1011 C/cm-2.

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