Abstract

The impacts of the substrate temperature on diverse microstructural, morphological, and optical features of the nickel oxide films deposited via spray pyrolysis were examined. The X-ray diffraction patterns revealed a dominant peak with (1 1 1) favored orientation for all the deposited samples. As the temperature went up from 350 to 450 °C, the indirect and direct band gap energies increased between 2.65 and 2.77 eV and from 3.80 to 3.89 eV, respectively. The thickness and the optical constants of the nickel oxide were estimated by fitting the measured Psi and Delta parameters by adopting a suitable optical model based on B-splines in the wavelength range of 380–900 nm. We obtained that the refractive index significantly decreased from 1.717 to 1.59. But, the extinction coefficient substantially augmented from 0.383 to 0.515. Furthermore, the values of the average oscillator and the dispersion energies were estimated by utilizing the Wemple-DiDomento model. At last, there was a correlation between the different sizes of the crystallite and the optical parameters of the nickel oxide thin films. The optical band gap increased while the refractive index and Urbach energy reduced with a rise in crystallite size.

摘要

研究了基底温度对通过喷雾热解沉积的氧化镍薄膜的各种微观结构、形态和光学特征的影响。X 射线衍射图显示所有沉积样品的主峰具有 (1 1 1) 有利取向。随着温度从 350 °C 升高到 450 °C，间接和直接带隙能量分别从 2.65 eV 增加到 2.77 eV，从 3.80 eV 增加到 3.89 eV。通过采用基于 B 样条的合适光学模型在 380-900 nm 波长范围内拟合测量的 Psi 和 Delta 参数，估算氧化镍的厚度和光学常数。我们发现折射率从 1.717 显着降低至 1.59。但是，消光系数从 0.383 大幅增加到 0.515。此外，平均振荡器和色散能量的值是通过利用 Wemple-DiDomento 模型来估计的。最后，微晶的不同尺寸与氧化镍薄膜的光学参数之间存在相关性。随着微晶尺寸的增加，光学带隙增加，而折射率和乌尔巴赫能量降低。