Structure and optical properties of Si thin film improved by metal Cd nanolayers

Abstract

Enhancing the characteristics of amorphous semiconductor thin films is imperative for a multitude of applications. The present study examines the impact of Cd nanolayers deposited on a thin film of amorphous Si. The X-ray test showed that the thin silicon film had less of an amorphous structure after a nanolayer of cadmium was added. There has also been the appearance of new phases, and as the thickness of the Cd nanolayer increases, so does the intensity of these phases. Using a field emission scanning electron microscope, it was seen that nanoparticles were developed and subsequently transformed into clusters as the thickness of the Cd nanolayer grew. The absorbance was maximized at 750 nm and near-infrared region after depositing Cd nanolayers, while transmittance was reduced, especially at 100 nm thicknesses. The energy gap was reduced, with a decrease from 5.1 to 1.8 electron volts (eV). However, an increase in the band tails was also noted, rising from 0.7 to 4.9 eV. An increase in the values of the refractive index (n) and extinction coefficient (k) was observed following the deposition of Cd nanolayers of different thicknesses.