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采用电子束蒸发法制备了PbI2多晶薄膜,研究制备条件对薄膜光电性质的影响。结果表明,不同条件下制备的样品呈现不同的择优取向生长特征,但均属于六方相多晶结构。随着衬底温度的升高,PbI2薄膜的紫外-可见透过谱透过性能提高,光学带隙由室温时的2.33 eV增大到200℃时的2.44 eV。同时发现,不同源-衬间距制备样品的光谱透过性能和光学带隙基本相同。光致发光谱(PL)测试表明,薄膜的发光可能源自禁带中的缺陷能级跃迁,其PL发光峰的强度和展宽随源-衬间距的增大有明显变化。论文最后测试了PbI2薄膜在绿光LED照射下的光电导响应,发现制备样品的光电导响应性能与薄膜的沉积温度和源-衬间距有密切关系,光电导率的数量级约在10-8~10-9Ω-1.cm-1之间。
PbI2 polycrystalline thin films were prepared by electron beam evaporation. The influence of the preparation conditions on the photoelectric properties of the thin films was studied. The results show that the samples prepared under different conditions show different preferred orientation growth characteristics, but belong to the hexagonal polycrystalline structure. As the substrate temperature increases, the UV-vis spectral transmittance of PbI2 thin films increases, and the optical band gap increases from 2.33 eV at room temperature to 2.44 eV at 200 ℃. At the same time, it was found that the spectral transmittance and optical band gap of samples prepared with different source-liner distances were basically the same. Photoluminescence (PL) measurements show that the luminescence of the thin film may be due to the defect level transition in the forbidden band, and the PL luminescence intensity and broadening change obviously with the increase of the source-liner spacing. The paper finally tests the photoconductive response of PbI2 thin films under green LED irradiation. It is found that the photoconductivity of the prepared samples is closely related to the deposition temperature and source-liner distance of the films. The photoconductivity is about 10-8 ~ 10-9Ω-1.cm-1 between.