Improved Performance of Titanium Oxide/Silicon Oxide Electron‐Selective Contacts by Implementation of Magnesium Interlayers
Yuta Nakagawa, Kazuhiro Gotoh, Tetsuya Inoue, Yasuyoshi Kurokawa, Noritaka Usami
Abstract
The impact of the implementation of magnesium interlayer and the layer thickness ( t TiO x ) of titanium oxide on the electrical properties of TiO x /SiO y /Si heterojunctions is investigated to improve electron transport for use in silicon heterojunction solar cells. The passivation performance is improved with increasing t TiO x . For the samples with Mg interlayer, ohmic contact can be attained for the thicker TiO x layer compared with the sample without Mg interlayer. Schottky contact is mitigated by the TiO x /SiO y stacking layers and Mg interlayer, attributed to the reduction of interfacial energy level by TiO x /SiO y stacking layers and enhanced downward band bending by Mg interlayer. The open‐circuit voltage and fill factor of the solar cells are improved by inserting the TiO x /SiO y stack and the Mg interlayer, indicating that the electron selectivity is enhanced. Excellent surface passivation and transport properties can be achieved by controlling TiO x layer thickness and using the Mg interlayer.