热致NiO_x薄膜的结构和光学性质变化

Structure and Optical Property Changes of Heat Induced NiO_x Thin Films

利用直流磁控反应溅射技术制备了氧气和氩气的分压比为5∶100的NiOx薄膜。利用X射线衍射仪（XRD）、扫描电镜（SEM）、原子力显微镜（AFM）和光谱仪研究了热处理对薄膜的微观结构和光学性质的影响,并对沉积态薄膜的粉末进行了热分析。沉积态的NiOx薄膜在262℃时开始分解,导致NiOx薄膜的透过率增加和反射率降低。X射线衍射和示差扫描量热曲线（DSC）分析表明,在热处理过程中并无物相的变化,光学性质的变化是由于NiOx薄膜热分解引起薄膜表面形貌发生变化而引起的。通过Kissinger公式计算出热分解所需克服的活化能为230.46kJ/mol,显示出很好的热稳定性。NiOx薄膜的热稳定性和热处理前后在波长为405nm处高的反射率差值,使其很有可能成为可录蓝光光盘的记录介质。

The NiOx thin films were deposited by reactive direct current （DC） magnetron sputtering from a nickel metallic target in Ar ＋ O2 mixed gases with the relative O2 content 5%. The effects of heat treatment on the microstructure and optical properties of NiO. thin films were studied by X-ray diffraction （XRD）, scanning electron microscope （SEM）, atom force microscopy （AFM） and spectrometer respectively. In addition, the powders of the as-deposited NiOx thin films were investigated by thermal analysis. The results showed that the decomposition temperature of the as-deposited NiOx thin films was at about 262 ℃. After annealed at 400 ℃ for 30 min in air, the reflectivity decreased and transmittance increased obviously. XRD and differential scanning calorimetry （DSC） analysis show that no phase transformation occured during the heating process, the changes of optical properties were related to the decomposition of NiOx thin films. The activation energy of decomposition of NiOx thin films was 230. 46 kJ/mol calculated by Kissinger formula, and the NiOx thin films have an excellent thermal stability. Its thermal stability and high optical contrast at 405 nm before and after annealing made it a good potential optical storage medium in write-once blue-ray disc.