PbS:Zn^(2+)纳米薄膜的化学水浴法制备研究

Synthesis and Characterization of Chemical-Bath Deposited PbS: Zn^(2+) Nano-Films

采用化学水浴法在抛光的p型Si(100)衬底上制备了本征Pb S及掺Zn的Pb S:Zn2+多晶纳米薄膜,采用X射线衍射谱、扫描电子显微镜、分光光度计和高阻仪着重研究了反应混合液中Zn2+的摩尔浓度(CZn)对薄膜微结构、近红外吸收特性及电学性质的影响。本征Pb S及Pb S:Zn2+薄膜均为多晶的立方结构且具有(200)择优取向;随着CZn的增大,(200)方向的平均晶粒尺寸(22~74 nm)基本上先减小后增大,表面颗粒的形状由起初的不规则趋于三角形和金字塔形。Pb S:Zn2+薄膜的吸收边随着CZn的增大先蓝移后红移,吸收边的蓝移归结于晶粒尺寸效应和(200)晶面上压应力的增大,而红移则归结于(200)晶面上晶粒尺寸的增大和压应力减小。随着CZn的增大,样品的电阻率先从1.31×105Ω·cm减小到1.0×102Ω·cm,然后再增大。这可能与纳米材料的量子局域效应和晶界处的微应变有关。

The intrinsic PbS and Zn-doped Pb S nano-crystalline films were synthesized by chemical bath deposition（ CBD） on substrates of heavily doped p-type Si（ 100）. The influence of the molar concentration（ CZn） on the microstructures and properties of the Pb S coatings was investigated with X-ray diffraction,scanning electron microscopy,and near-infrared absorption spectroscopy. The results show that the Zn-doping significantly affects the microstructures and optical and electrical properties of the Pb S coatings. To be specific,as the CZnincreased,the absorption edge of the coatings shows the blue-shift followed by a red-shift; the size of the（ 200） preferentially grown grains changed in a decrease-increase mode,accompanied by the formation of triangles and pyramids,and the resistivity varied in a decrease-increase way,increasing after decreasing from 1. 31 × 10^5 to 1. 0 × 10^2Ω·cm,possibly because of the quantum confinement and the localized micro-strains at grain-boundary.