Structural and Electrical Properties of Spin-Coated LaF3 Thin Film on Porous Silicon

Rare-earth halides like lanthanum fluoride (LaF3) are an extensively used material for sensors and optical devices. Generally, different sophisticated and expensive techniques have been used for the epitaxial deposition of LaF3 thin film to make heterostructure devices. In a quest of finding a facile technique of depositing LaF3 films, this report presents the deposition of LaF3 thin film on porous silicon substrate by reacting lanthanum chloride (LaCl3) with hydrofluoric acid (HF) directly on spinning porous silicon (PS) substrate. Nearly stoichiometric and polycrystalline LaF3 was confirmed by the energy-dispersive x-ray spectroscopy (EDS) and x-ray diffraction (XRD) analysis, respectively. The crack-free homogeneous morphological structure was confirmed by scanning electron microscopy (SEM). From the capacitance- voltage (C-V) and current-voltage (I-V) characteristics, it was observed that the spin-coated LaF3/PS structure shows capacitive nature as well as diode nature, respectively. From the experimental results, it can be concluded that lanthanum fluorides can be deposited into the pores as well as on the top of PS by the spin-coating technique, which provides the required passivation for PS. This passivation can enable the PS to be considered as an important material for electronic device fabrication.