Assessment of interfacial layer thickness of pulsed laser deposited plasmonic copper thin films via spectroscopic ellipsometer

The thickness of interfacial layer of semitransparent nanostructured plasmonic copper thin films fabricated on the glass substrate via pulsed laser deposition, as a function of deposition time, using spectroscopic ellipsometry is reported. The top oxide layer was identified as Cu2O having the thickness in the range of 2.47 nm-3.29 nm. The phase of interfacial layer is found to be changing from cupric oxide to cuprous oxide with the increase in deposition time and the thickness was found to increase from 0.25 to 0.61 nm for the deposition time of 6-10 min respectively. Longitudinal and transverse SPR modes were identified from SE measurements and were found to be in agreement with that of measured directly via UV-Visible spectrometer. The band gap energy of the top Cu2O layer was observed to be similar to 2.02 eV.