Patterning of nanopillars-based CdS/CdTe thin films for photonic applications

In this study we propose a new design to place the contacts for both p-type and n-type semiconductors at the bottom of solar cell to increase photons entering the absorber layer. The fabricated device contains periodic nanopillars of ∼243 nm radius and centre to centre pillar distance of ∼550 nm. In addition to the fabrication, thin films of n-CdS and p-CdTe have been characterised for their material properties at different annealing temperatures in this study. The X-ray diffraction pattern for CdTe and CdS revealed that the growth is preferentially along the (111) plane with a cubic zinc blend and cubic structure, respectively. Optimum absorption of the solar spectrum for a single junction solar cell occurs with the optical band gap of 2.36 eV for CdS and 1.45 eV for CdTe. The significance of the work creates a new beginning for the fabrication of textured thin film photovoltaic cell.