Laser-induced crystallization in Ga15Se81Zn4 chalcogenide thin films

Abstract

. Ga 15 Se 81 Zn 4 chalcogenide thin films having thickness 300 nm, prepared by vacuum evaporation technique were crystallized by Nitrogen Laser for 10, 20 and 30 min. As-synthesized and laser-crystallized films were analyzed by X-ray diffraction, field emission scanning electron microscopy (FESEM), UV/VIS/NIR spectroscopy and dc conductivity measurements. The observed optical band gap becomes smaller by inducing laser-crystallization period 0 to 30 min, which is due to the crystallization of amorphous films. The lowering of band gap by laser-crystallization is an interesting behavior for a material to be used in various electronic devices. The dc conductivities of as-synthesized and laser-crystallized films were analyzed at different temperatures from room temperature to 400 K. We have noticed that the dc conductivity becomes larger at different temperatures under investigation at different laser-crystallization time. Similar to behavior of optical band gap, the dc conductivity activation energy is also observed to become slower with increasing laser-crystallization time and there is a good compliance between these two values.