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

摘要

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 Cul, 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 Cul films show p-type conduction with hole mobility and a concentration of 17.3 cm~2/V~(-1) s~(-1) and 1.1 × 10~(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 6.2 × 10~3.