An anti-reflective 1D rectangle grating on GaAs solar cell using one-step femtosecond laser fabrication

- 1D rectangular gratings were fabricated on GaAs solar cell surface.
- We examine changes in morphology of the structure fabricated with different parameters.
- The structure fabricated shows a great anti-reflective effect in large wavelength ranges.
- We conduct simulation using a finite-difference-time domain (FDTD) method on 1D rectangular grating.

We report the fabrication of the anti-reflective micro/nano-structure on absorbing layer of GaAs solar cell surface using an efficient approach based on one-step femtosecond laser irradiation. Morphology of the microstructures and reflectance of the cell irradiated are characterized with SEM and spectrometer to analyze the influence of laser processing parameters on the change of microstructures induced and the reflectance. It has been found that the rectangle grating micro/nano-structure with a period of 700 nm and width of 600 nm is obtained neatly with laser pulse energy of 30.5 μJ(pulse duration is 130 fs, center wavelength is 800 nm, scanning speed is 2.2 mm/s and spot diameter is 22 µm). Reflectance has been suppressed to 23.6% with rectangle structure from 33% of planar cell. In addition, simulation using a finite-difference-time domain(FDTD) method results show that the rectangle grating micro/nano-structure can effectively suppress the reflection within large wavelength ranges.