铝掺杂氧化锌薄膜的光学性能及其微结构研究

以氧化铝(Al2O3)掺杂的氧化锌(Zn O)陶瓷靶作为溅射靶材,采用射频磁控溅射工艺在玻璃基片上制备了具有c轴择优取向的铝掺杂氧化锌(Zn O:Al)薄膜样品.通过可见-紫外光分光光度计和X射线衍射仪的测试表征,研究了生长温度对薄膜光学性能及其微结构的影响.实验结果表明:薄膜性能和微观结构与生长温度密切相关.随着生长温度的升高,样品的可见光平均透过率、(002)择优取向程度和晶粒尺寸均呈非单调变化,生长温度为640 K的样品具有最好的透光性能和晶体质量.同时薄膜样品的折射率均表现为正常色散特性,其光学能隙随生长温度升高而单调增大.与未掺杂Zn O块材的能隙相比,所有Zn O:Al薄膜样品的直接光学能隙均变宽.

Optical Properties and Microstructure of Aluminum-Doped Zinc Oxide Thin Films

The c-axis preferred orientation aluminum-doped zinc oxide （ ZnO：Al ） thin films were deposited on glass substrates by RF magnetron sputtering using the ceramic target fabricated by sintering the mixture of Al2 O3 and ZnO nanometer powder.The growth temperature was varied from 570 K to 710 K during the magnetron sputtering process.The optical properties and microstructure of the deposited films were investigated by ultraviolet-visible spectrophotometer and X-ray diffractometer.The results indicated that the optical properties and microstructure of the samples are closely related to the growth temperature.As the growth temperature increasing, the average transmittance in the visible range, degree of preferred orientation and grain size of the samples change nonmonotonically.The thin film deposited at the substrate temperature of 640 K has the highest optical transmittance and the best crystal quality.Meanwhile, the deposited thin films possess the normal dispersion characteristics in visible region.The optical energy gaps of the samples are observed to increase monotonically when the growth temperature increases.Compared with the optical energy gap of undoped ZnO, the direct energy gaps of all the deposited films are broadened.