MY EXPERIMENTS WITH THIN-FILMS - THE NANOSTATE OF MATTER

The black art of thin films exhibiting whimsical properties and thus c alled 'the fourth state of matter' enticed the author to a challenge t o unravel the mysteries of matter created ab-initio on a nanoscale. Nu cleation and growth studies of evaporated and sputtered films (both po lycrystalline and epitaxial) and the effects of kinetic energy, angle of incidence, electric field, substrate agitation, formation of metast able and amorphous structures, etc led to exciting discoveries. The fi elds of amorphous metal alloy and semiconducting films were thus born. Electron and optical transport investigations on pure and doped metal , semiconducting, oxide and polymer films established a variety of new phenomena of which the mean free path effects and specular scattering of conduction electrons in epitaxial metal films, giant thermopower i n quenched metal films, sputter quenching, giant photocontraction effe ct in amorphous Ge-chalcogenide films, enhancement of superconducting transition temperature in transition metal films, nanosize multi layer coating (the first known superlattices) are noteworthy. A variety of new deposition processes such as solution growth of polymer films, sol ution growth of chalcogenide and oxide films, spray pyrolysis, copreci pitation of multicomponent oxides (for thick films), activated reactiv e evaporation/magnetron sputtering were innovated. This lecture will s hare the excitement of the contributions by the author, his 60 Ph. D s tudents and a number of post doctoral fellows and faculty members at t he Thin Film Laboratory, IIT Delhi and the Microscience Laboratory at IIT Kharagpur.