不同衬底和CdCl2退火对磁控溅射CdS薄膜性能的影响

在科宁7059玻璃, FTO, ITO, AZO四种衬底上磁控溅射CdS薄膜, 并在CdCl₂+干燥空气380 ℃退火, 分别研究了不同衬底和退火工艺对CdS薄膜形貌、结构和光学性能的影响. 扫描电子显微镜形貌表明: 不同衬底原位溅射CdS薄膜的形貌不同, 退火后相应CdS薄膜的晶粒度和表面粗糙度明显增大. XRD衍射图谱表明: 不同衬底原位溅射和退火CdS薄膜均为六角相和立方相的混相结构, 退火前后科宁7059玻璃, FTO, AZO衬底上CdS薄膜有 H(002)/C(111) 最强衍射峰, ITO衬底原位溅射CdS薄膜没有明显的最强衍射峰, 退火后出现 H(002)/(111) 最强衍射峰. 紫外-可见分光光度计分析表明: AZO, FTO, ITO, 科宁7059玻璃衬底CdS薄膜的可见光平均透过率依次减小, 退火后相应衬底CdS薄膜的可见光平均透过率增大, 光学吸收系数降低; 退火显著增大了不同衬底CdS薄膜的光学带隙. 分析得出: 上述结果是由于不同衬底类型和退火工艺对CdS多晶薄膜的形貌、结构和带尾态掺杂浓度改变的结果. 关键词： CdS薄膜 磁控溅射 退火再结晶 带尾态

Effects of different substrates and CdCl2 treatment on the properties of CdS thin films deposited by magnetron sputtering

CdS films were deposited on corning 9059 glass, FTO, ITO and AZO substrates by r.f. magnetron sputtering, and annealed at 380 ℃ in CdCl₂+ dry air. Effects of different types of substrate and thermal annealing on the morphology, structure and optical properties were investigated. Field emission scanning electron microscope shows: the morphology of as-deposited and annealed CdS thin films on different substrates is different, grain size and surface roughness increase significantly with annealing. XRD diffraction patterns show: the structure of as-deposited and annealed CdS thin films on different substrates are mixed phase structure of hexagonal and cubic phases, there is a preferential orientation of the crystallits with the hexagonal (002) and cubic (111) peak for as-deposited and annealed CdS films on corning 9059 glass, FTO, and AZO substrates, for as-deposited CdS film on ITO substrate there is no preferentially oriented diffraction peaks, but has highly oriented with hexagonal (002) or cubic (111) peak after annealing; UV-Vis spectrophotometer spectrum analysis shows: the average transmittance in visible spectrum of CdS thin films deposited on AZO, FTO, ITO and Corning 7059 glass substrates in turn decreases, annealing increases the corresponding substrate of CdS films in visible light transmittance, reduces the optical absorption coefficient; annealing significantly increases the band gap of CdS films on different substrates. Analysis reveals that the performance comes from the result of different types of substrate and annealing process for morphology and structure of CdS thin films, and the band tail states changes, due to variation of doping concentration.
Keywords： CdS thin films magnetron sputtering annealing and recrystallization band tail states