CdTe solar cells fabrication and examination techniques: a focused review

There has been an increasing demand for green energy due to the negative impact of global warming on the environment and life. This has necessitated the fabrication of different semiconductor materials using various methods for solar cell and photovoltaic applications. Cadmium telluride (CdTe) is a polycrystalline thin film and has emerged as a leading material for the development of cost-effective and reliable photovoltaic systems because of its near-ideal bandgap for high photovoltaic conversion efficiency and optical absorption coefficient. The CdTe has excellent resistivities of 10⁷-10⁹ Ω cm, carrier densities of 10⁹-10¹¹ cm⁻³, and mobility ca. cm² V⁻¹ s⁻¹. Development has been made in terms of optimizing the fabricating of CdTe thin films with efficiencies increasing above 22%. The addition of copper (Cu) doping has been used to increase the Cdte efficiency through a controlled amount of Cu employed in the annealing process. The characterization tools used to understand the structures of the fabricated CdTe solar cells are discussed and it was revealed from the Atomic Force Microscope that increasing the grain size reduces the non-radiative recombination for higher performance of the solar cell. Finally, the achievements and prospects of CdTe solar cells for future development are presented.