Dependency of built-in potential of LaF3/porous-silicon heterostructure prepared by chemical bath deposition technique on the concentration of LaCl3 and annealing temperature

摘要

Effect of LaCl₃ concentration and annealing temperature on the built-in potential of LaF₃/PS heterojunction has been investigated in this report. LaF₃ layers have been deposited by a novel chemical bath deposition (CBD) technique. With this simple technique LaF₃ produced as LaCl₃ are made to react with hydrofluoric acid on the porous silicon (PS) substrate. This enables direct deposition of LaF₃ on the pore walls of the PS leading to a successful passivation of PS. The compositions of the deposited LaF₃ were confirmed by energy dispersive of X-ray analysis. The built-in potential decreases with LaCl₃ concentration and increases with annealing temperature. Therefore, by changing the LaCl₃ concentration and annealing temperature quality of the LaF₃ layer on PS can be optimized. From the experimental results it can be concluded that lanthanum fluorides can be deposited on the PS surface by the CBD technique, which provides the required passivation for PS. This passivation can enable the PS to be considered as an important material for photonics