Carbon Nanotube Network P-N Junction Diodes: Exploring the Dark and Light Properties

Semiconducting carbon nanotubes are attractive for photovoltaic applications because of their large variation of chiralities, which makes it possible to absorb a broad range of the solar spectrum. Here, we fabricate a network of CNTs and form P-N diodes using buried split gates. We study the intrinsic optical properties of the CNT network without the need for electron or hole acceptor material. We study the diode properties of both monochiral and polychiral networks, including those fashioned into tandem cells. We examine the current-voltage characteristics of these diodes in the dark and find correlations between the key figure of merits, including the diode leakage current and the ideality factor, to different CNT networks. We also examine their optical properties by measuring the photocurrent spectroscopy to gain insights into the dynamics of excitons in a network of CNTs.