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采用电子束蒸发工艺在普通玻璃衬底上制备了PbI2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PbI2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,PbI2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PbI2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2.42eV,随着衬底温度升高而略微增大,显示结晶质量提高。
PbI2 polycrystalline thin films were prepared on common glass substrates by electron beam evaporation. The effects of different substrate temperatures on the structure, surface morphology and UV-Vis spectra of the films were investigated. The XRD results show that the PbI2 thin films deposited at different substrate temperatures are hexagonal, and show the c-axis preferred growth at (002) at low temperatures. However, the preferred growth is weakened with increasing substrate temperature. The SEM morphology analysis The results show that the grain size of PbI2 films increases with the increase of substrate temperature, meanwhile the protrusions caused by the intergranular stress decrease and the surface density and flatness of the films increase. The results of UV spectrum show that the different substrate temperature The absorption bands of the prepared PbI2 thin films were all around 515 nm and showed steep absorption edges. Calculations show that the forbidden band width of the film is about 2.42 eV, slightly increasing as the substrate temperature increases, indicating that the crystal quality is improved.