Carbon nanotube/silicon heterojunctions for photovoltaic applications

Photovoltaic devices have rapidly developed in recent years as they seek to address the ever-increasing energy requirements and environmental issues. Due to their simple structure and easy, low-temperature fabrication, heterojunctions of carbon nanotube (CNT) films and silicon (Si) have been used in solar cells, photodetectors and optoelectronic gas sensors. Significant progress has been made on the development of high-performance CNT/Si heterojunction devices, in particular, CNT/Si solar cells. Here, we give a comprehensive overview of state-of-the-art CNT/Si heterojunction devices. The effects of the structure of the CNTs, the interface layer and the silicon structure on the performance of CNT/Si solar cells are analyzed. In addition, potential ways to further improve the performance of such photovoltaic devices are proposed. Finally, the key challenges and developing trends in CNT/Si heterojunction photovoltaic devices are discussed.