电子束蒸发制备PbI_2薄膜及其性能表征

采用电子束蒸发工艺在普通玻璃衬底上制备了PbI_2多晶薄膜,研究了不同衬底温度对薄膜结构、表面形貌及紫外-可见光谱的影响.XRD结构表征显示,不同衬底温度下沉积的PbI_2薄膜均属六方结构,低温下呈现(002)方向的c轴择优生长,但随着衬底温度的升高,择优生长弱化;SEM形貌分析结果表明,PbI_2薄膜的晶粒尺寸随着衬底温度的升高而增大,同时晶粒间应力造成的突起减少,薄膜表面致密度和平整度提高;UV光谱测试结果表明,不同衬底温度下制备PbI_2薄膜透过光谱的吸收限均在515nm附近,且呈现陡直的吸收边.计算发现,薄膜禁带宽度约为2.42 eV,随着衬底温度升高而略微增大,显示结晶质量提高.

Abstract：

Polycrystalline lead iodide (PbI_2) thin films were deposited on glass substrates by electron beam evaporation method.The influence of different substrate temperatures on the structure,surface morphology and optical transmittance of the films was studied.XRD analysis shows the PbI_2 films deposited at different temperatures possess hexagonal structure,with a preferred growth orientation of (002) at low temperature,but this preferred growth characteristic vanishes when the substrate temperature increases.SEM micrograph reveals the grain size of PbI_2 thin films increases with the rising substrate temperature,meanwhile,the surface bulges resulted from the strain between grains decrease,making the surface of the films more compact and uniform.UV transmittance shows the steep absorption edge is at 515 nm for all samples grown under different substrate temperatures and the corresponding band gap is about 2.42 eV.

Characterization and Preparation of PbI_2 Thin Films Grown by Electron Beam Evaporation

Polycrystalline lead iodide (PbI_2) thin films were deposited on glass substrates by electron beam evaporation method.The influence of different substrate temperatures on the structure,surface morphology and optical transmittance of the films was studied.XRD analysis shows the PbI_2 films deposited at different temperatures possess hexagonal structure,with a preferred growth orientation of (002) at low temperature,but this preferred growth characteristic vanishes when the substrate temperature increases.SEM micrograph reveals the grain size of PbI_2 thin films increases with the rising substrate temperature,meanwhile,the surface bulges resulted from the strain between grains decrease,making the surface of the films more compact and uniform.UV transmittance shows the steep absorption edge is at 515 nm for all samples grown under different substrate temperatures and the corresponding band gap is about 2.42 eV.