Influence of Magnetic Field and Temperature on the Charge Carrier Transport Parameters in a Radial Junction Solar Cell

Abstract

This study examines the combined influence of magnetic field and operating temperature on charge-carrier transport parameters in a polycrystalline silicon radial junction solar cell. The analysis focuses on carrier mobility, diffusion coefficient, and diffusion length, which are central to the collection of photogenerated carriers and the photovoltaic performance of the device. The results indicate that increasing temperature reduces carrier mobility because of stronger carrier–phonon interactions. This reduction in mobility also decreases the diffusion coefficient and diffusion length, thereby limiting the ability of charge carriers to reach the junction before recombination. The applied magnetic field also affects transport behaviour through the Lorentz force, which deflects carriers from their initial trajectories and reduces their effective mobility and drift velocity. At low magnetic fields, below 10⁻⁴ T, the diffusion coefficient and diffusion length remain nearly constant. In the intermediate range of 10⁻⁴ T to 10⁻² T, both parameters decrease progressively, while for magnetic fields above 10⁻² T, strong carrier confinement produces a marked limitation of transport. The maximum diffusion length is approximately 20 µm near room temperature, around 300 K, in the absence of a magnetic field or under very weak magnetic fields. These findings indicate that a base radius close to 20 µm is suitable for improving carrier collection in the studied radial junction configuration.