Infrared 45° reflectometry: A new approach to characterize nanostructured epifilms and superlattices

International Conference and Exhibition on Mesoscopic & Condensed Matter Physics

June 22-24, 2015 Boston, USA

Devki N Talwar

Indiana University of Pennsylvania, USA

Posters-Accepted Abstracts: J Material Sci Eng

Abstract :

By exploiting a 45�?°-IR methodology we have performed comprehensive simulations of �?�?45 spectra to justify its ability for directly identifying and measuring the long wavelength transverse optical (TO) and longitudinal optical (LO) phonons in MBE grown strained nanostructured polar ZnTe(CdTe), Cd1-xZnxTe epifilms and (CdTe)m/(ZnTe)n SLs overlaying GaAs (001) substrates. It is demonstrated that the oblique-incident far-infrared (OI-FIR) reflectivity and transmission spectra show insignificant changes to the resonance phonon frequency features of epifilms even if the film thickness is modified by hundreds of nanometers. For the nanostructured epitaxial samples grown on different substrates, we strongly believe that measuring �?�?45 spectra is more pragmatic than the OI-FIR transmittance as it exhibits remarkable sensitivity to film thickness.

Biography :

Devki N Talwar received his BS (1968), MS (1970) from Agra University and PhD (1976) from Allahabad University in India. From 1977-1980, he worked as a visiting scientist at the Commissariat à l'Energie Atomique (CEA), Saclay (France). He came to the US in 1980 and worked at the University of Houston from 1980-1982, and then at Texas A&M University from 1982-1987 as a visiting Assistant professor. In 1987 he joined the Physics faculty at Indiana University of Pennsylvania (IUP). During his tenure at IUP he has been awarded several grants from various research agencies including the National Science Foundation (NSF), Research Corporation, US Air Force, American Chemical Society, and National Research Council (NRC). He also received numerous academic awards including the University Professorship – the highest honor from IUP faculty and administration. In 1993, he organized an International Materials Research Society (MRS) Symposium during the Fall Meeting in Boston and edited all the research papers presented in the Symposium. Besides Teaching and Service responsibilities at IUP, his research has been directed toward investigating the role of defects in semiconductors, nanostructure materials, quantum wells and superlattices, for electronic and optoelectronic applications.

Email: talwar@iup.edu