Swift heavy ion irradiation induced modifications in CdTe and CdS thin films
The effect of Swift Heavy Ion (SHI) irradiation on semiconductor materialsand devices is of significance both from fundamental as well asapplication aspects. Interesting phenomena like phase transformation incrystalline solids, sputtering of target material, surface and interfacemorphological changes, modification of optical band gap, etc have beenreported on thin films of metals/semiconductors. The II-VI compoundsemiconductors such as CdTe and CdS are widely studied for their provenapplications in optoelectronic devices such as solar cells, detectors,light emitting diodes, etc. Since the properties have strong dependence onthe preparation conditions and post deposition treatments, interest on themodification of thin film properties with the aid of novel techniques hasincreased. In this constitution, the successful exploitation of SHIirradiation to induce modifications in the properties of CdTe and CdS thinfilms has been studied. The evaporated films of CdTe and CdS wereirradiated with 100 MeV silver and 80 MeV oxygen ions and the propertieswere studied by X-ray diffraction, scanning electron microscopy (SEM),atomic force microscopy (AFM), optical absorption/transmittance,photoluminescence, and X-ray photoelectron spectroscopy. Upon irradiation,most of the important properties such as grain size, stress, optical bandgap, electronic structure, and native defects show significant changes
30/12/2007 at 4:00 pm
Prof. X.Vinas, Department of Physics, University of Barcelona, Spain
We have seen by now all the basic constituents of matter(quarks & leptons) along with the carriers of the basic forces (i.e.gauge bosons). But the story is not complete yet. A consistent theory of their masses requires the presence of Higgs bosons along with Supersymmetric particles, which we hope to discover at LHC. Discovery of theseparticles will also throw light on the nature of phase transition theUniverse went through a few picoseconds after its creation, and the nature of Dark Matter that permeates throughout the Universe today as a relic of that early history.