First-principles identification of V I  + Cu i defect cluster in cuprous iodide: origin of red light photoluminescence

• Published in: Nanotechnology Vol. 33; no. 19; p. 195203
• Main Authors: Liu, Dingrong, Cai, Zenghua, Wu, Yu-Ning, Chen, Shiyou
• Format: Journal Article
• Language: English
• Published: England 07.05.2022
• Subjects: transparent semiconductor; carrier density; photoluminescence; defect cluster; first-principles calculation; cuprous iodide
• ISSN: 0957-4484; 1361-6528
• DOI: 10.1088/1361-6528/ac4aa5

The -phase cuprous iodide (CuI) emerges as a promising transparent p-type semiconductor for next-generation display technology because of its wide direct band gap, intrinsic p-type conductivity, and high carrier mobility. Two main peaks are observed in its photoluminescence (PL). One is short wavelength (410-430 nm) emission, which is well attributed to the electronic transitions at Cu vacancy, whereas the other long wavelength emission (680-720 nm) has not been fully understood. In this paper, through first-principles simulations, we investigate the formation energies and emission line shapes for various defects, and discover that the intrinsic point defect clusterVI+Cui2+is the source of the long wavelength emission. Our finding is further supported by the prediction that the defect concentration decreases dramatically as the chemical condition changes from Cu-rich to I-rich, explaining the significant reduction in the red light emission if CuI is annealed in abundant I environment.