厚度对溶胶-凝胶法制备锂掺杂ZnO薄膜性能的影响

EFFECTS OF THICKNESS OF Li-DOPED ZnO FILMS GROWN BY SOL-GEL METHOD ON THEIR PROPERTIES

采用溶胶–凝胶旋涂法在玻璃衬底上制备了不同厚度的ZnO:Li半导体薄膜。采用X射线衍射仪和扫描电子显微镜分析了薄膜的物相结构和形貌,用Hall效应测量仪常温下测量薄膜的电学性能。结果表明:该薄膜具有高度的c轴择优取向性,所有薄膜只有1个(002)衍射峰,并且衍射强度随着膜厚增加而加强。ZnO:Li薄膜晶粒呈柱状,晶粒直径不随膜厚改变,约为40nm。ZnO:Li薄膜为p型导电,薄膜越厚,其电学性能与晶体结晶越好,(002)方向择优取向生长越明显。电阻率随着膜厚增加而减小,最小的电阻率为1.32×102(Ω·cm)。载流子–空穴浓度为3.546×1016/cm3,迁移率为1.34cm2/(V·s)。ZnO:Li薄膜在可见光范围内的透过率达到90%,薄膜对紫外光的吸收与厚度有关。

Li-doped ZnO thin films with different thicknesses were fabricated on a glass substrate by the sol-gel spin coating method. The phase structure and surface morphology of the films were analyzed by X-ray diffraction and scanning electron microscopy. The electric properties of the films were measured by a Hall effect tester at room temperature. The results show that the films exhibit highly （002） oriented growth in all the cases, and the intensity of the （002） peak becomes stronger with increasing thickness. The average grain size of the films is 40nm. All film samples exhibit p-type conductivity. The resistivity of Li-doped ZnO films decreases with the increase of the thickness of film. The film with a thickness of 210nm has optimal properties, with a resistivity of 1.32 x 102 （Ω.cm）, a Hall mobility of 1,34 cm^2/（V.s）, and a hole concentration of 3.546 × 10^16/cm^3. The ultraviolet-visible spectra show that the optical transmission of the film is high （〉90%） in the visible region, and its absorption in the ultraviolet region depends closely on the thickness of the film.