Electroluminescence of Sm3+ ions in semiconducting polycrystalline zinc oxide

Abstract

Characteristic emissions at 575, 615 and 665 nm have been observed in a three-electrode electrochemical cell under anodic polarization for Sm³⁺ ions inserted into a semiconducting zinc oxide electrode. The electroluminescence intensity varies with the square-root of the reciprocal of the applied potential according to the Alfrey–Taylor equation. The intensity of the light emitted increases with dopant concentration and reaches a maximum for ca. 0.5 atom% of Sm³⁺ in ZnO; above this concentration the light intensity decreases. Structural analysis of a polycrystalline sample by scanning electron microscopy indicates that the inserted rare-earth ions induce important dislocations in the polycrystalline structure and do not substitute for zinc in the crystal lattice.