Wide-range tuning of optical constants in DC sputtered MoS2/ITO thin films

MoS2 and ITO thin films have been among the most studied materials in recent decades because of their extensive and wide usage in opto-electronic equipment. The optical characteristics of these materials can further be tuned by making their composites. In this context, DC magnetron co-sputtering mechanism was utilized for the deposition of MoS2, ITO and MoS2/ITO composite thin films on Si substrate. X-ray diffraction confirmed the hexagonal structure for MoS2 and body centered cubic structure for ITO. Energy dispersive X-ray spectroscopy was employed to ascertain the chemical composition of thin film samples. A better uniformity of the grains was observed for MoS2/ITO composites as compared to pure MoS2 films, exhibited by scanning electron microscopic images. Moreover, optical characterizations were carried out by spectroscopic analysis powered by ellipsometry in terms of psi/Delta values, attained through appropriate fitting model, correlated with the calculated data. Real part showed that significant variation in refractive index values were observed for high energy range whereas imaginary part depicted that low absorption spectra had occurred at low energy range. A vertical inhomogeneity dip in MoS2/ITO composite was encountered due to the phase changing phenomena. Owing to the subsequent nature of MoS2/ITO composite thin films, it was investigated that high reflectance of light was observed at large wavelength close to IR region, whereas the composite showed good absorption at smaller values of wavelength. The whole analysis depicted that MoS2/ITO composite thin films could extravagantly be used in optical devices like ultra-susceptible label free molecular devices owing to its peculiar optical tailoring.

Automated summary

MoS2 and ITO thin films are extensively studied materials due to their wide usage in opto-electronic equipment. Composite thin films of MoS2/ITO showed improved uniformity of grains compared to pure MoS2 films. Optical analysis revealed that MoS2/ITO composite thin films have great potential for use in optical devices due to their unique optical properties.