Local current-voltage behaviors of preferentially and randomly textured Cu(In,Ga)Se₂ thin films investigated by conductive atomic force microscopy

Electrical transport properties on polycrystalline Cu(In,Ga)Se₂ (CIGS) (Ga/(In+Ga) ≈ 35%) thin films were examined by conductive atomic force microscopy. The CIGS thin films with a (112) preferential or random texture were deposited on Mo-coated glass substrates. Triangular pyramidal grain growths were observed in the CIGS thin films preferentially textured to the (112) planes. Current maps of the CIGS surface were acquired with a zero or nonzero external voltage bias. The contrast of the images on the grain boundaries and intragrains displayed the conduction path in the materials. Local current-voltage measurements were performed to evaluate the charge conduction properties of the CIGS thin films.