Silicon heterojunction solar cells with electron selective TiO sub(x) contact

• Published in: Solar energy materials and solar cells Vol. 150; pp. 32 - 38
• Main Authors: Yang, Xinbo, Zheng, Peiting, Bi, Qunyu, Weber, Klaus
• Format: Journal Article
• Language: English
• Published: 01-06-2016
• Subjects: Contact; Electrical resistivity; Heterojunctions; Passivation; Photovoltaic cells; Silicon; Solar cells; Titanium oxides
• ISSN: 0927-0248
• DOI: 10.1016/j.solmat.2016.01.020

Silicon solar cells featuring carrier selective contacts have been demonstrated to reach ultra-high conversion efficiency. In this work, the electron-selective contact characteristics of ultrathin TiO sub(x) films deposited by atomic layer deposition on silicon are investigated via simultaneous consideration of the surface passivation quality and the contact resistivity. Thin TiO sub(x) films are demonstrated to provide not only good passivation to silicon surfaces, but also allow a relative low contact resistivity at the TiO sub(x)/Si heterojunction. A maximum implied open-circuit voltage (iV sub(oc)) of ~703 mV is achieved with the passivation of a 4.5 nm TiO sub(x) film, and a relatively low contact resistivity of (~0.25 Omega cm super(2) is obtained at the TiO sub(x)/n-Si heterojunction simultaneously. N-type silicon solar cell with the champion efficiency of 20.5% is achieved by the implementation of a full-area electron-selective TiO sub(x) contacts. A simulated efficiency of up to 23.7% is achieved on the n-type solar cell with a full-area TiO sub(x) contact. The efficient, low cost electron-transporting/hole-blocking TiO sub(x) layer enables the fabrication of high efficiency silicon solar cells with a simplified process flow.