Wide Band Gap Al and In Co-doped ZnO Films for Near-Infrared Plasmonic Application

In transparent conducting oxide films, tuning of plasmonic resonance is directly controlled by free electron concentration and thus by activated dopants. In this study, large area AlxInyZn1-x-yO thin films at various concentrations were prepared by spray coating using water as a solvent. The effect of Al/In dopant ratio on the structural, electrical, optical, and plasmonic properties was investigated. Tuning of optical response to a well-defined plasmon resonance is correlated to the above properties of AlxInyZn1-x-yO films. Theoretical fitting based on the Drude-Lorentz (D-L) theory was utilized for extracting the dielectric spectra and cross-over wavelength (omega(c)). The studies revealed plasmonic properties in NIR for the films with Al/In ratios of A(5)I(5), A(2.5)I(7.5), and A(0)I(10), indicating In as the most activated dopant. Surface plasmon mode simulated using the extracted permittivity values showed the influence of mobility of these films on the broadening of the dip. The minimum plasmonic loss suggests the suitability as an alternative plasmonic material in the near infrared.

Automated summary

In this study, large area AlxInyZn1-x-yO thin films were prepared by spray coating and the effect of Al/In dopant ratio on their structural, electrical, optical, and plasmonic properties was investigated. The results showed that films with different Al/In ratios exhibited distinct plasmonic properties in the near infrared region, with In being the most activated dopant. The minimum plasmonic loss observed suggests the potential suitability of these films as alternative plasmonic materials in the near infrared.