Variation of various properties of LaF3 deposited on porous silicon by chemical bath and spin coating techniques

Lanthanum fluoride (LaF3) is an extensively used material for sensors, optical, and electronic devices. Generally, different sophisticated and expensive techniques have been used for the deposition of LaF3 film to make heterostructured devices that hinders its mass production. The structural, compositional, and electrical properties of LaF3 heavily depend on the deposition techniques. This report presents an investigation of the variation of the structural or morphological, compositional, and electrical properties of LaF3 caused by two very low-cost deposition techniques, called chemical bath and spin-coating, on porous silicon (PS) substrate. In both deposition techniques, LaF3 was synthesized by reacting LaCl3 with hydrofluoric (HF) acid directly on the PS surface. The morphological and compositional properties of deposited LaF3 films were investigated by Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) analysis, respectively. The spin coated LaF3 contains less lanthanum, fluorine, and oxygen than chemical bath deposited LaF3. The current–voltage (I–V) and capacitance–voltage (C–V) characterization confirmed the insulating or dielectric nature of the deposited LaF3 in the Ag/LaF3/PS/Ag structure. I–V and C–V characteristics also revealed the production of more leakage current and less capacitance by the spin-coated LaF3/PS structure than the chemical bath-deposited LaF3/PS structure. The experimental results indicate that both spin coating and CBD techniques can deposit LaF3 into the pores of PS for passivation of PS. These simple techniques of passivation of PS may enable the PS to be an important material for electronic device fabrication.