不同温度硫化生长ZnS薄膜的性能

采用磁控溅射方法在玻璃衬底上室温下沉积了Zn薄膜,接着将薄膜在硫蒸气和氩气氛中于200℃预热1 h,然后升温至250~500℃退火1 h。以XRD、SEM、EDS和紫外可见分光光度计对薄膜进行表征,并结合热力学计算结果研究了Zn薄膜硫化生长机理。Zn转变为ZnS的过程包括硫化反应以及S原子和Zn原子的扩散。研究还表明:第一步的200℃预热可在Zn薄膜表面形成ZnS,随后第二步退火的硫化温度对硫化薄膜光透过率、S/Zn摩尔比和结晶性都有明显影响;在大于或等于300℃的硫化温度下制备的ZnS薄膜在400~1100 nm范围光透过率高达约80%,带隙为3.54~3.60 eV,晶体结构为六方。

Properties of ZnS thin films prepared by different-temperature sulfidation

Zn thin films were deposited on the glass substrates at room temperature by magnetron sputtering.And then these Zn thin films were pre-heated at 200℃for 1 h and subsequently annealed at 250-500℃for 1 h in an atmosphere of sulfur-vapor and Ar.The properties of the samples were analyzed by XRD(X-ray diffractometer),SEM(scanning electron microscopy),EDS(Energy Dispersive Spectrometer)and UV-VIS spectrophotometer.The conversion mechanism of Zn thin films was investigated in combination with thermodynamical calculation.The Zn-to-ZnS conversion includes the sulfidation reaction,and atomic diffusions of S and Zn.It was found that the initial pre-heating at 200℃lead to the formation of ZnS on the Zn film surface,and sulfidation temperature in the subsequent annealing had an obvious effect on the optical transmittance,S/Zn molar ratio and crystalline of the sulfurized thin films.ZnS thin films prepared by sulfidation at a temperature over 300℃had the hexagonal structure with the band-gap energies from 3.54 eV to 3.60 eV.This film exhibited the optical transparency of about 80%in the 400-1100 nm region.