Princeton University

School of Engineering & Applied Science

Interface Recombination in TiO2/Silicon Heterojunctions for Silicon Photovoltaic Applications

Janam Jhaveri
Prof. Sturm
Engineering Quadrangle J401
Friday, May 18, 2018 - 10:00am to 11:30am

Solar photovoltaics (PV), the technology that converts sunlight into electricity, has immense potential to become a significant electricity source. Nevertheless, the laws of economics dictate that to grow from the current 2% of U.S. electricity generation and to achieve large scale adoption of solar PV, the cost needs to be reduced to the point where it achieves grid parity. For silicon solar cells, which form 90% of the PV market, a significant and slowly declining component of the cost is due to the high-temperature (> 900 °C) processing required to form p-n junctions.
In this work, the replacement of the high-temperature p-n junction with a low-temperature amorphous titanium dioxide (TiO2)/silicon heterojunction is investigated. The TiO2 layer is deposited, characterized and then optimized through low temperature annealing for interface passivation. A new measurement technique, the heterojunction bipolar transistor (HBT) method, is developed to analyze the current mechanisms across a TiO2/Si heterojunction and matched with an analytical model to explain the current mechanisms.