Effect of substrate temperature on structural and optoelectronic properties of thermally evaporated CuBr nanofilms

The cuprous bromide (CuBr) nanofilms were deposited via thermal evaporation, and the influence of substrate temperature on their optical and electrical properties was systematically investigated to evaluate their potential for integration into optoelectronic devices. Current research on thermally evaporated CuBr thin films has primarily employed them as hole transport layers in optoelectronic devices. However, the CuBr exhibits a sharp blue excitonic emission peak at approximately 410 nm, a unique photoluminescence (PL) characteristic that suggests its viability as an emissive layer for light-emitting devices. The as-deposited CuBr thin films prepared in this work exhibit a polycrystalline zinc-blende structure with smooth surface morphology and good uniformity. Notably, the films show a high transmittance exceeding 80% in the visible spectral range, and the PL spectra reveal a prominent emission peak at approximately 412 nm for the as-deposited films, consistent with the intrinsic emission features of CuBr. With the increase of substrate temperature, the crystallinity of the films was improved, accompanied by enhanced PL intensity and reduced resistivity. These results demonstrate that the CuBr nanofilms deposited by thermal evaporation provide a material and processing foundation for the subsequent construction of CuBr-based electroluminescent devices.