Abstract
Gallium arsenide is a high-performance while expensive photovoltaic material. How to reduce the cost remains the major issue for GaAs-based photovoltaic. In this study, the Ga-assisted VLS growth technique was applied to the fabrication of GaAs nanowires based solar cells on Si substrates, which can reduce the cost. In the first part of this thesis, we used electron-beam lithography to form periodic pinhole arrays in the oxide layer. We found that the beam dose (μC cm-2) determined the pinhole diameter, while the pitch controlled the pinhole density. Thereafter, we studied the influences of pinhole diameter and density on the morphology of GaAs nanowires. In the second part, we fabricated the solar cell devices based on PEDOT:PSS and GaAs nanowire arrays. The PEDOT:PSS has been one of the most promising conducting polymers and can act as a p-type semiconductor material. The PEDOT:PSS thin film was first deposited onto the indium tin oxide (ITO) conductive glass by spin coating. Then, the GaAs nanowire arrays were put onto the conductive glass to fabricate the GaAs/PEDOT:PSS hybrid solar cell device. The effects of the nanowire length and diameter as well as the spin coating speed on the performance of hybrid devices were investigated. The best power conversion efficiency achieved in this work is 0.136%.