Effect of Al-doping on morphology, structure, and optical band gap of ZnO thin films synthesized by sol-gel spin-coating technique

Thin films of undoped and Al-doped ZnO were produced, and their surface morphology, structure, and optical characteristics were researched. The thin films were produced on glass substrates using the sol-gel spin-coating technique, with Al-doping concentrations of 1.5 and 2.5%. We observed from our structural analysis that, a decrease in grain size after adding Al dopants. Similarly increase in dislocation density (inversely proportional to Crystallinity) was observed after adding Al dopants. According to the SEM data, it is found that the undoped ZnO's particles are spherical type in shape and agglomerated. The related histograms and distribution curve demonstrate that when Al-dopant concentration rises, the spherical shape particle becomes thinner, indicating a reduction in particle size. Based on the optical transmittance spectrum, the films' undoped transmittance, which is 75% within the visible wavelength range, falls with rising Al-dopant concentration. Band gaps of the films were observed to decrease with increasing Al-dopant percentage.

Automated summary

The surface morphology, structure, and optical characteristics of undoped and Al-doped ZnO thin films were investigated. Thin films were prepared on glass substrates using the sol-gel spin-coating technique, with Al-doping concentrations of 1.5% and 2.5%. Structural analysis revealed a decrease in grain size and an increase in dislocation density after adding Al dopants. Scanning electron microscopy data showed that undoped ZnO particles were spherical and agglomerated, while the particle size decreased and transmittance decreased with increasing Al-dopant concentration according to the related histograms and distribution curve. Additionally, band gaps of the films were observed to decrease with increasing Al-dopant percentage.