Effect of Different Properties of Cu(In1-xGax)Se2 Thin Films Synthesized by Femtosecond and Nanosecond Pulsed Laser Deposition

Two kinds of pulsed laser sources, femtosecond laser (fs laser) and nanosecond laser (ns laser), were used in the pulsed laser deposition (PLD) system to synthesize copper indium gallium selenium (CIGS) thin films at the substrate temperature from room temperature (RT) and 500 degrees C. Different surface morphology, crystallinity, and stoichiometric ratio were observed on CIGS thin films deposited by femtosecond pulsed laser deposition (fs-PLD) and nanosecond pulsed laser deposition (ns-PLD) respectively, that resulted in different optical and electrical properties. It is proposed that the laser absorption of CIGS target with different laser wavelength caused the difference in laser penetration depths into the target, so that the stoichiometric ratio of the evaporated materials splashing from the target were different between fs-PLD and ns-PLD processes.