Biennial Report 2005-2007 - Saha Institute of Nuclear Physics

Material Physics 1835.2 Plasma Physics5.2.1 Experimental Studies5.2.1.1 Visible Raman Spectroscopy of thin Carbon filmsIn this work we show the importance of the visible Raman spectroscopy in reliably predicting thekey properties of diamond-like Carbon (DLC) films. The correlations between properties of hydrogenateddiamond-like Carbon (HDLC) films and their Raman spectra have been investigated. Thehydrogen concentration, sp 3 content, hardness, optical Tauc gap and nanocrystanility of the filmshave been estimated from a detail analysis of their Raman spectra. We have also measured thesome parameters of the films by using other commonly used techniques like sp 3 content in filmsby x-ray photoelectron spectroscopy, their Tauc gap by Ellipsometric measurements and harnessby micro-hardness testing. The results obtained using these probes and that from Raman analysishave been comparedNR Ray, D Das, SS Sil, A Bal, A Betal, A Roy†, A Singha†PP5.2.1.2 Optical properties of thin Carbon films by EllipsometryWe have measured the density of states of sp 3 and sp 2 electrons in the DLC films using Ellipsometricmeasurements and compared the results with Raman measurements. Also refractive index (n)vs wavelength (λ) and extinction coefficient (k) vs wavelength (λ) are obtained from Ellipsometricmeasurements. The result shows that the carbon film has more than 80% transmission in IR region.NR Ray, J Engemann†, J Raacke†PP5.2.1.3 Transmission electron microscopy (TEM) of thin Carbon filmsSample for TEM has been prepared by dimpling and ion milling from the substrate side so as toget electron transparent thin region of the film in large area. Sample was characterized by TEM inboth imaging and diffraction mode. The diffraction pattern, as shown in Fig.5.2.1.3a, from one ofthe region shows the single crystal like diffraction.