Multicrystalline silicon thin film solar cells based on vanadium oxide heterojunction and laser doped contacts
in: Physica Status Solidi A-Applications and Materials Science (2019)
Liquid phase crystallized (LPC) silicon thin films on glass substrates are a feasible 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 the combination of vanadium oxide/c-Si heterojunction as emitter and base contacts defined by IR laser processing of phosphorus-doped amorphous silicon carbide stacks is explored. LPC solar cells are fabricated using such technologies in order to identify their issues and advantages with a promising performance of an active-area efficiency of 5.6%. Apart from the absence of light trapping techniques, the relatively low efficiency obtained is attributed to a low lifetime in the LPC silicon bulk. These poor material properties imply a short diffusion length that makes that only photogenerated carriers in the emitter regions could be collected. Consequently, future devices should show narrower base contact regions, suggesting a shorter-wavelength laser, combined with longer LPC substrate lifetimes.