Fabrication and electrical properties of LiNbO3/ZnO/n-Si heterojunction

Lithium niobate (LiNbO3 or LN) ferroelectricfilms were grown on n-type Si (100) substrates using ZnO as buffer layers by pulse laser deposition technique. The microstructures and electrical properties of the heterojunctions were studied. X-ray diffraction results showed that single (001) orientation for the LN films can be promoted on Si (100) substrates with the buffer effect of the ZnO layers. Due to the ferroelectricpolarizations of the LN films,hysteretic characteristicswere observed from the capacitance-voltage (C-V) curves of the LN/ZnO/n-Si heterojunctions. Obvious photoresponse characteristics were exhibited in the fabricated heterojunction. High performance of the photoresponse of the heterojunction was shown, such as a large ON/OFF ratio, short photoresponse time, steady ON or OFF states, and well reversible. These characteristics make it possible for the heterojunctions to develop multifunctional applications, such as memory devices,eletro-optic devices, and etc. The studied results show that the electrical properties of the heterojunctions were dependent greatly on the thickness of the ZnO buffers and the structural composition of the LN films. The results were discussed in terms of the band diagrams of the LN/ZnO/Si heterojunctions in this work.