Enhanced Optical Absorption of Ti Thin Film: Coupled Effect of Deposition and Post-deposition Temperatures

Abstract

In the present work, structural, morphological and optical properties of nanostructured titanium (Ti) thin films have been studied. The Ti thin films were fabricated on glass substrate by direct current (DC) magnetron sputtering at varying deposition and post-deposition temperatures (T DA) ranging from 373 K to 773 K. The microstructure and morphology of the Ti thin films were found to be highly dependent on T DA. The root mean square surface roughness (δ rms) was found to increase with T DA up to 673 K and then decreased at 773 K. The absorption (A) of Ti films has shown a similar trend as roughness with T DA; however, the reflection (R) has shown an opposite trend. Maximum A ~99–86% and minimum R ~1–14% were observed in the spectral range of 300–1100 nm for the sample fabricated at T DA = 673 K, which exhibited the highest δ rms ~193 nm. Due to its excellent absorption, this film may be a potential candidate for photonic applications such as a super-absorber.