Alshomar S M, Attia Mohamed S, Akl Alaa Ahmed, Fathy Naglaa, Albaqawi Hissah Saedoon, Affan Hira, Mohamed Ehab Sabry, Amin Lamiaa G, Mahmoud Safwat A
Department of Physics, College of Science, University of Hail, Box 2440, Hail, Saudi Arabia.
Chemistry Department, Faculty of Science, Ain Shams University, Abbassia, Cairo, 11566, Egypt.
Heliyon. 2024 Aug 23;10(17):e36783. doi: 10.1016/j.heliyon.2024.e36783. eCollection 2024 Sep 15.
This work investigates the compositional dependence and thermal annealing of the morphological properties, electrical conductivity mechanisms and Mott's parameters of sprayed MoWO (x = 0, 0.05, 0.10 and 0,20) thin films. The prepared thin films were examined using field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray analysis (EDX) and Fourier transform infrared spectroscopy (FTIR) techniques. In addition, the two-point probe method was used to calculate the electrical properties of MoWO thin films. The FTIR results revealed that; the tungsten hydroxyl bond (W-OH) and the surface hydroxyl group vibrated within the ranges of 1558.62-1645.56 cm and, 3296.76 and 3424.34 cm, respectively. Furthermore, a prominent band in the spectrum spanning from 850 to 650 cm represents the W-O-W bridge mode. The FE-SEM investigations found that the molybdenum (Mo) dopant caused significant changes in the surface morphology of the films. The EDX results showed that the percentages of the isotropic elements MoWO agreed well with those obtained by atomic weight. Studies of the conduction mechanism indicate that the transition temperature was approximately 393K. Corresponding to Mott's model, the conduction mechanism below this temperature was across the variable hopping conduction band near the Fermi level. The mechanism exhibited a cycle of localised states through activated thermionic emission above 393K. Mott parameters were also estimated in addition to barrier potential energies, trapping state energies, local state densities, and other variables. The results revealed that both temperature areas had a rise in ρ and ρ values during and after annealing. The ΔE and ΔE values in each temperature area decreased as the Mo-ion concentration increased. Furthermore, the conversion temperature gradually reduced as Mo was added. Based on these properties, the study's overall findings indicate that MoWO is suitable for future photonic devices and optoelectronic applications.
本工作研究了喷雾法制备的MoWO（x = 0、0.05、0.10和0.20）薄膜的形态特性、电导率机制及莫特参数的成分依赖性和热退火情况。使用场发射扫描电子显微镜（FE-SEM）、能量色散X射线分析（EDX）和傅里叶变换红外光谱（FTIR）技术对制备的薄膜进行了检测。此外，采用两点探针法计算MoWO薄膜的电学性能。FTIR结果表明；钨羟基键（W-OH）和表面羟基分别在1558.62 - 1645.56 cm和3296.76及3424.34 cm范围内振动。此外，在850至650 cm光谱范围内的一个显著波段代表W-O-W桥模式。FE-SEM研究发现，钼（Mo）掺杂剂使薄膜的表面形态发生了显著变化。EDX结果表明，各向同性元素MoWO的百分比与通过原子量获得的结果吻合良好。传导机制研究表明，转变温度约为393K。对应于莫特模型，在此温度以下的传导机制是通过费米能级附近的可变跳跃导带。在393K以上，该机制通过激活热电子发射表现出一个局域态循环。除了势垒势能、俘获态能量、局域态密度和其他变量外，还估算了莫特参数。结果表明，在退火期间和之后，两个温度区域的ρ和ρ值均有所上升。随着Mo离子浓度的增加，每个温度区域的ΔE和ΔE值均降低。此外，随着Mo的添加，转变温度逐渐降低。基于这些特性，该研究的总体结果表明，MoWO适用于未来的光子器件和光电子应用。
