Giant lateral photovoltaic effect in the TiO2/SiO2/p-Si heterostructure

In this work, we study the lateral photovoltaic effect in the TiO2/SiO2/p-Si structure. It was found the giant lateral photoeffect occurs in the TiO2/SiO2/p-Si heterostructure due to the high built-in barrier formation at the SiO2/p-Si interface. The maximum LPE sensitivity ~600 mV/mm is observed in the TiO2/SiO2/p-Si structure under the TiO2 film deposition for 45 min. However, the LPE nonlinearity in this structure is too large for practical applications. A decrease of the nonlinearity is achieved by the TiO2 film thickness control. The structure fabricated by the TiO2 film deposition for 50 min has the LPE sensitivity and LPE nonlinearity are 477 mV/mm and 9%, respectively, which are more suitable for optoelectronic devise. The reason for the significant values of the rise time and fall time at pulsed illumination is the impedance behaviors of the TiO2/SiO2/p-Si structure in the near-contact region.