Multicristalline silicon thin film solar cells based on vanadium oxide heterojunction and laser doped contacts
in: IEEE Journal of Photovoltaics (2020)
Liquid phase crystallized (LPC) silicon thin films on glass substrates are a feasible cost-effective alternative to conventional crystalline silicon (c-Si) wafers for solar cells. Due to substrate limitation, a low temperature technology is needed for solar cell fabrication. While silicon heterojunction is typically used, in this work we explore the combination of vanadium oxide/c-Si heterojunction as emitter whereas base contacts are defined by IR laser processing of phosphorus-doped amorphous silicon carbide stacks. LPC solar cells are fabricated using such technologies in order to identify their issues and advantages. First solar cells were finished with promising performance of 558 mV and 5.6%. Apart from the absence of light trapping techniques, the obtained efficiency is attributed to a low lifetime in the LPC silicon bulk compared to conventional silicon wafers, which implies a short diffusion length. As a consequence, only photogenerated carriers in the emitter regions are collected. Consequently, future devices should show narrower base contact regions, suggesting a shorter-wavelength laser, combined with longer LPC substrate lifetimes.
DOI: Array