Solution-processed amorphous p-type Cu-Sn-I thin films for transparent Cu-Sn-I/IGZO p-n junctions

P-type Cu-Sn-I thin films with different Sn contents (C-Sn) were fabricated in air via a simple and low-cost spin-coating method. Sn additive facilitates the amorphization of CuI, and a complete amorphous phase of Cu-Sn-I film is achieved at C-Sn =15%. With increasing C-Sn, the optical bandgap increases and refractive index decreases, probably due to the influence of Sn-additive on both the electronic structure and phase state of the films. The air-processed Sn-free CuI films show p-type conduction with hole mobility and a concentration of 17.3cm(2)/V-1 s(-1) and 1.1x10(19)cm(-3), and an increasing trend of resistivity is observed along with a large drop in hole concentration during the Sn-inspired amorphization process. Moreover, transparent Cu-Sn-I/IGZO p-n junctions were constructed, exhibiting the optimum rectifying characteristic at C-Sn=15% with a forward-to-reverse ratio of 6.2x10(3).

Automated summary

The addition of Sn influences the electronic structure and phase state of the films, leading to an increase in optical bandgap and a decrease in refractive index as Sn content increases. The Sn-free CuI films processed in air exhibit p-type conduction, with an increasing resistivity and a significant drop in hole concentration during the Sn-induced amorphization process. Transparent Cu-Sn-I/IGZO p-n junctions show the best rectifying characteristic at C-Sn=15%, with a forward-to-reverse ratio of 6.2x10(3).