The effect of plasma irradiation is studied systematically on a 4H polytype (002) oriented CdI2 stoichiometric film having compressive residual stress. Plasma irradiation was found to change the orientation to (110) of the film at certain moderate irradiation distances. A linear decrease in grain size and residual stress was observed with decreasing irradiation distance (or increasing ion energy) consistent with both structural and morphological observations. The direct optical energy gap Eg was found to increase linearly at the rate 15µeV/atm with the compressive stress. The combined data of present compressive stress and from earlier reported tensile stress show a consistent trend of Eg change with stress. The iodine-iodine distance in the unit cell could be responsible for the observed change in Eg with stress.

The manuscript reports the variation in optical band-gap of vacuum annealed SnS thin films. The samples were characterized by using X-Ray Diffraction, Scanning Electron Microscopy (SEM), UV-visible Spectroscopy and Raman Analysis. Results show that while annealing does not effect the nano-crystalline

The amorphous-to-crystalline phase change induced by a continuous-wave Ar + laser was investigated systematically in the case of as-grown amorphous films of Sb 2 S 3 , Sb 2 Se 3 and Sb 2 Te 3 and results were compared. The photo-thermal process is found to be responsible for the phase change in all three compounds. The minimum threshold laser power required to induce optical contrast at an irradiated site was found to depend on the film thickness; however, the required power density was found to be of the order of 100 W cm −2 for all three films. All three films exhibited good potential for use as the WORM kind of storage devices, Sb 2 Se 3 films having the minimum threshold power. Sb 2 Se 3 and Sb 2 Te 3 films in the non-stoichiometric phase exhibited potential for reversible storage.

The Sb 2 S 3 films subjected to instantaneous heat treatment at various temperatures in air for a short duration of a few seconds show a systematic phase modification from an amorphous to a crystalline state. Structural and morphological analyses show an amorphous to crystalline transformation around 162°C consistent with the DTA result. The compositional analysis ͑ESCA͒ shows an increasing loss of sulphur content in the film as the function of treatment temperatures. The optical properties reveal the changing optical constants and energy gap of the film with the treatment temperatures. The observed degree of optical contrast with heat-treatment temperatures indicates the possibility of photo-thermal optical storage in these films. The results of the real-time photo-thermal optical recording in these films compare well with those of the heat-treatment experiment. The homogeneity of the film over a large area, the stability of the modified phase, use of low laser power for recording, and the formation of a clean boundary of the recorded area, etc., indicate a possible use of Sb 2 S 3 films for write-once-read-many times kind of optical storage applications.

MnCo2O4 catalyst with an octahedral geometry and 2.11 eV band gap was developed for visible light driven photocatalytic water splitting considering the crucial roles of Co(iii)OH, and cobalt(ii) oxide and Mn3+ in Co3O4 and Mn2O3 photocatalysts for water splitting.