Preparation Of Rare Earth Doped Bismuth Chloride Thin Films And Study On Their Luminescent Properties

High performance semiconductor thin-film technology is an important foundation of the current microelectronics, photonics and new materials industry. Rare earth doped semiconductor thin film materials have broad application prospects due to the the rare earth ion’s rich optical physical properties and the advantages of the semiconductor thin films. Development has unique optoelectronic properties of new rare earth doped semiconductor thin film materials has important theoretical and practical significance to research and development for small or micro optoelectronic devices, therefore, it has been attracted more and more attention from researchers and institutions.BiOCl is a new type of indirectly semiconductor photocatalytic with broadband gap, its unique layered structure can form a induced electric field in [001] direction of the crystal, that make the BiOCl showed a excellent physical and chemical properties. The research found that the induced electric field also gives the rare earth ions a unique luminescence property as the rare earth ions activator matrix. Moreover, the crystal structure gives BiOCl a two dimensional oriented, this make it has natural advantages as thin film. It is well known that because of the lower dimensional of the film it will show many peculiar physical and chemical properties. And it will derived a excellent physical and chemical properties and become a new type of rare earth doped semiconductoer thin film material. So far, however, the rare earth doped BiOCl is rarely reported. Therefore we put forward in this paper that preparation a nano thin film with rare earth doped. We research the rare earth ions’ luminescence behavior on influence factors and mechanism through the film morphology, orientation control and using Precious metal ions or external ions. And further more, with combination the connection of the above way and photocatalytic performance, we studied the possibility of studies the catalytic properties by rare earth doped fluorescence in semiconductor thin film.We prepared the Er³⁺ doped BiOCl thin film through hydrolysis-coating. We get the films with different crystal face exposed by control the coating times. Under the excitation of 980nm light source, we found a special ohoton avalanche with the excitation power reach a certain threshold. With the single nanosheet does not changed, the luminous intensity of the film with {010} crystal face exposed is 24 times of the film with{001} crystal face exposed. Under the ultraviolet excitation, the photocatalytic is also the same. In previous study, the result is opposite.Through the analysis of crystal structure, we discussed relationship between the special induced electric field and the upconversion luminescence.In silver nanoparticles doped BiOCl:Er³⁺ thin film, we found that with the addition of Ag, the upconversion luminous intensity and the catalytic properties both has improved. Different with the traditional semiconductor optical properties enhancement by Ag, in this process, Ag nanoparticles does not enhanced the lumious intensity by surface plasmon resonance effect, but by forming local electric field. The local electric field stack with the internal electric field of BiOCl and enhanced the electric field. The increasing electric field enhanced the lumious intensity and catalytic activity of the film.In Li+ doped BiOCl:Er³⁺ thin film, we found that the doping of Li+ ions make the luminescence intensity of the film has remarkable enhancement. But in this process, Li+ ions did not play as a Crystal modifier. Characterized by XPS、and lumious life time, we found that the doped Li+ ions does not get into the crystal lattice to change the crystal symmetry, but gathered into the double chlorine atom layers or absorbed to the face of nanosheet to make the nanosheet more thinner. And through this way, the internal electric field enhanced. Yb³⁺ ions doping also showed a special luminescence. First, the doped Yb³⁺ ions did not play like sensitizer to make the lumines intensity enhanced. Secondly, Yb³⁺ ions doping makes the avalanche phenomenon behavior gradually disappear. We think the doped Yb³⁺ ions can changed the energy transfer process between the energy levels, and make the upconversion mechanism changed.