Physical mechanism of current conduction and light emission in high-resistivity ZnS:Mn thin films

Abstract

Thin films of ZnS doped only with implanted Mn display the characteristic strong yellow 585 nm peak electroluminescent emission at high electric field intensities in the absence of additional activation by either Cu or Cl. Emission is obtained only above a threshold field of about 0.45 × × 106 V cm−1, with a maximum brightness in the region 40 to 70 ft la and maximum quantum and power efficiencies of 4.1% photons electron−1 and 1.5 × 10−1% W W−1, respectively. A mechanism of bulk‐limited conduction leading to electroluminescence by impact excitation of the Mn centre is unambiguously deduced from examination of the experimental and theoretical data. Mean free paths for the low‐field electron‐LO phonon interaction energy loss of 8.2 to 11.3 Å are measured for several films.