Fine structures of conduction and intermediate bands of NaBiO3•2H2O/NaBiO3•xH2O heterostructures investigated by surface photovoltage measurement with external bias

The fine structures of conduction and intermediate bands of semiconductors determine photoelectronic properties of devices, whose investigation is developed with surface photovoltage(SPV) measurement. With external bias, the differences of SPV intensities at 400 and 375 nm of NaBiO3 center dot 2H(2)O/NaBiO3 center dot xH(2)O heterostructures increase with temperature and reach the maximum for the sample heated at about 110 degrees C. The SPV at about 470 nm NaBiO3 center dot 2H(2)O/NaBiO3 center dot xH(2)O heterostructures (30 degrees C) is enhanced about 8.8 times after ethanol treatment. The results suggest that the possible excited state corrsponding to 3.1 eV (400 nm) above the conduction band bottom is better matching conduction band of NaBiO3 center dot 2H(2)O than that corresponding to 3.3 eV (375 nm). The intermediate band within band gap corresponding to 2.6 eV (470 nm) due to ethanol treatment inducing surface defects contributes to the enhanced SPV. The investigation suggests that the SPV measurement is a helpful tool to investigate the fine structures of conduction and intermediate bands of NaBiO3 center dot 2H(2)O/NaBiO3 center dot xH(2)O heterostructures and related photovoltaic and catalytic materials.

Automated summary

This study investigates the influence of fine structures of conduction and intermediate bands on the photoelectronic properties of NaBiO3·2H(2)O/NaBiO3·xH(2)O heterostructures using SPV measurement. The results show that the SPV intensity differences increase with temperature and peak around 110 degrees C, while treatment with ethanol leads to a significant enhancement in SPV intensity at 470 nm. The findings highlight the importance of SPV measurement in studying the microstructures of conduction and intermediate bands in heterostructures for potential applications in photovoltaic and catalytic materials.