CdTe Thin Film Solar Cells Fabricated With CuO as a Buffer Layer in the Back Contact

The choice of back contact plays a key role in the fabrication of a CdTe thin film solar cell. Material with low electric resistivity, relatively high work function, and thermal stability is needed to form a low barrier contact on a CdTe absorber film. In this work, thin CuO layer was employed as a buffer layer between p-type CdTe and metal electrode. Quantitative band alignment measurement demonstrated that a relatively low energy barrier (similar to 0.44 eV) was formed at the CuO/CdTe interface. CdTe solar cell stability was significantly enhanced when a CuO buffer layer and less Cu were employed in the back contact.