Cost is the most important parameter that a solar industry focusses on. Efforts are being made to improve the solar cell efficiency. However, the performance enhancement is targeted without increasing the cost of solar cell fabrication. Looking at the global PV market, advanced solar cell designs are set to dominate over conventional Al-BSF cells. Dielectric film at the rear of these cells plays a very important role in terms of both electrical as well as optical aspect. We, here at NCPRE have custom- designed a spray-coater tool for the deposition of thin silicon dioxide (SiO 2 ) films. The spray- coating deposition is simple, cost-effective, and industrially viable. In addition, it has an advantage over other the solution processed techniques, such as spin- and dip-coating in terms of deposition uniformity over industrial scale size samples with high throughput. Spray coater is different from the spray-pyrolysis system in a way that in the spray-coating process, the solution is sprayed over a cold substrate, which is further subjected to a thermal treatment for drying and densification. Using this custom-designed spray-coater tool, we have demonstrated ~10 nm thin uniform and stoichiometric SiO 2 film with excellent interface and passivation properties.
Jayshree Bhajipale and Anil Kottantharayil, “Passivation of n- and p-type Silicon Surfaces with Spray- coated Sol-gel Silicon Oxide Thin Film”, IEEE Transactions on Electron Devices, 67 (2020) 5045 -5052, DOI: 10.1109/TED.2020.3025981.