Swift heavy ion irradiation induced microstructural transformation in selenium thin films

The structural, morphological and optical properties of selenium thin films are important for the application in electronic and optoelectronic devices. In the present work, the effect of annealing in vacuum at different temperatures (130 degrees C, 160 degrees C and 200 degrees C) and swift heavy ion irradiation (Ag9+ ions with energy of 120 MeV) at different fluences (5 x 10(11), 1 x 10(12), 5 x 10(12) and 1 x 10(13) ions/cm(2)) on various properties of thermally deposited Se thin films has been investigated. The phase transition from amorphous to crystalline (t-Se) phase has been achieved with annealing followed by ion irradiation. Raman spectral analysis also confirms the trigonal phase of selenium in annealed and ion irradiated thin films. The morphology of films is found to be dependent on annealing temperature and ion fluence. The growth of nano-rods is observed in the preannealed (130 degrees C), irradiated (5 x 10(11) ions/cm(2)) selenium thin film. Optical properties also have been found to be tailored with annealing temperature and ion fluence.