Abstract：In order to further study the separation and transport mechanism of photogenerated charges,and the main influence factors in heterojunctions composite system, Zn2SnO4 rhombic nanoparticles and order nanowires were synthesized on stainless steel filters by hydrothermal method. Zn2SnO4 / ZnFe2O4 heterojunctions were prepared with two kinds of different Zn2SnO4 microstructures and ZnFe2O4 as inorganic sensitizer.XRD results indicate that two components of heterojunction sturcture can be a good crystalline state,at the same time,two heterojunctions all present the absorption characteristics of composite structure. The signals of steady state surface photovoltage indicate that two heterostructures exhibit the higher photovoltaic response than two components. Moreover,Zn2SnO4 nanowires / ZnFe2O4 presents the higher photovoltaic response than Zn2SnO4 nanoparticles / ZnFe2O4. Under the lower positive bias,two heterojunctions have the same surface photovoltage as the steady state. With the bias increasing,the photovoltaic response of Zn2SnO4 nanoparticles /ZnFe2O4 enhances quickly. Under bias of + 2 V,Zn2SnO4 nanoparticles / ZnFe2O4 exhibits the similar photovoltaic signal with Zn2SnO4 nanowires / ZnFe2O4. It is suggested that photoanode microstructure,density of carrier,free charges diffusion length,thickness of surface space charge region,build-in electric field and energy level matching have a direct effect on the separation and transport of photogenerated charges.

Keyword：surface photovoltage spectroscopy;photovoltaic response;Zn2SnO4/ ZnFe2O4;heterojunction;