Tio2(001) surface of rutile TiO2 single crystals was studied by surface photovoltage spectrum (SPS) and electrical field-induced surface photovoltage spectrum (EFISPS)techni(lue. The two SPS responses peak at 360 nm and 410 nm were identified as direct transition and indirect transition of TiO2(001) plane, respectively. And it was found that the indirect transition of TiO2 was very sensitive to the external electrical field. These results indicate that SPS and EFlSPS are effective means to study the opto-electrical characteristics ofsemico nd uctors.
We used polarized surface photovoltage spectroscopy (PSPS) to study the photovoltage response of TiO\-2 single crystal (001) surface. Besides a band\|band transition at 355 nm and a indirect transition at 410 nm, we observed a new photovoltaic response at 380 nm in the PSPS spectrum which was assigned to the transition with relation to the surface state. Under different polarized directions, the intensity of photovoltaic responses at 380 nm and 410 nm changed regularly, which proved that the two transitions were interrelated to the atomic arrangement on the TiO\-2 single crystal (001) surface.
The photovoltaic properties of dimeric porphyrin have been studied by means of surface photovoltage spectrum(SPS) and field induced surface photovoltage spectrum(FISPS). The results show that a negative SPV response band(P) appears in the long wave region which takes on n type character and the π π * transition band takes on p type character. P band disappears under high vacuum and appears under O 2 atmosphere. The photo charge transfer process generated between π π * transition band of dimeric porphyrin and P band, which has been attributed to the photo adsorption and photo desorption of O 2 on the surface of dimeric porphyrin.
In the present work, we prepared two kinds of quantum sized ZnO particles whose size were 3 nm(P1) and 5 nm(P2), respectively, and studied their surface properties with surface photovoltage spectroscopy(SPS) and electric field induced surface photovoltage spectroscopy(EFISPS). The photovoltaic response of the two samples showed opposite dependence on external electric field. And when electric field was applied, the thresholds of photovoltaic response of the two samples were all red shifted. The results showed that the surface properties of P1 were different from those of P2, because of their different preparation process. We assigned that basic zinc acetate structure exist on the surface of P1 sample. While for P2 sample prepared by aging P1, that kind of surface structure disappeared, but the particles might be doped with lithium ions in the aging process.
