Transparent p-type CuBr 1%x I x semiconducting thin films with a variable band gap were prepared using spin coating, which is a non-vacuum process. The dependence of their structural and optical properties on the CuBr 1%x I x composition was investigated. In X-ray diffraction patterns, the dominant CuBr 1%x I x peak was found to shift to higher angles with decreasing mixing ratio x. The Z 1,2 and Z 3 exciton absorption bands were observed from 300 to 400 nm, and the absorption wavelength varied with x. The ionization potential was determined using photo yield spectroscopy, and was found to increase with increasing x. These results suggest that the valence band maximum for CuBr 1%x I x depends on the composition. The results obtained in the present study allowed the energy band structure for this material to be proposed.

A transparent fine structure of p–n junctions using zinc oxide nanorods with different aspect ratios and CuBr1-xIx was prepared by the solution coating method. The structures and electrical properties of the p–n junctions were characterized by scanning electron microscope, X-ray diffraction and current–voltage measurements. Clear rectification characteristics were obtained from all the samples. The leak current in the reverse direction was small in the p–n junction with large diameter nanorods. In the p–n junction with short nanorods, the rise of forward current was steep and a large current flowed. Carrier generation by UV light irradiation was confirmed from all p–n junctions.