Red–Orange Luminescence of Undoped Copper Iodide Crystals at 80–300 K

Abstract

Orange and red photoluminescence spectra of copper iodide were studied and divided into four components with λmax ≈ 625–635 (O1), 635–655 (O2), 725–735 (R1), and 735–755 nm (R2) that were explained by possible association of the corresponding glow centers (GCs) with donor–acceptor pairs (DAPs) responsible for CuI edge luminescence. A generation-recombination scheme for red–orange luminescence was developed based on Auger interaction of GCs and DAPs. Intrinsic interstitial Cu defects acted as GCs for red CuI luminescence. Methods for controlling CuI luminescence characteristics by annealing crystals (in I2 vapor, in vacuo), doping with Li, or saturation of samples with electrodiffused Cu were demonstrated.