Laser-induced crystallization in Ga15Se81Zn4 chalcogenide thin films

Ga15Se81Zn4 chalcogenide thin films having thickness 300 nm, prepared by vacuum evaporation technique were crystallized by Nitrogen Laser for 10, 20 and 30 min. Assynthesized 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 lasercrystallization 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 assynthesized 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 lasercrystallization time and there is a good compliance between these two values.