Green Electroluminescence from Metal--Oxide--Semiconductor Devices Fabricated by Spin Coating of Terbium Organic Compounds on Silicon

Current--voltage ($I_{\text{G}}$--$V_{\text{G}}$) and electroluminescence (EL) characteristics are reported for indium--tin oxide (ITO)/Tb--Si--O layer/n + -Si metal--oxide--semiconductor (MOS) devices. The Tb--Si--O layer was fabricated from a Tb organic compound film, which was spin-coated on an n + -Si substrate and annealed with temperatures from 700 to 1000 \mbox{ \circ C} for 30 min in air. The EL intensity increased proportionally to the supply current, and it also increased with annealing temperature at the same current. The EL device emitted green light with four photon energy peaks at 2.52 eV (492 nm), 2.27 eV (547 nm), 2.11 eV (589 nm), and 1.99 eV (623 nm), which originated from the intrashell transitions of 5 D 4 -- 7 F J ($\mathit{J}= 6$, 5, 4, and 3) of Tb 3+ ions excited by hot electrons. The surface layers on the Si substrate have a total thickness of about 30 nm and consist of a Tb 2 O 3 layer, and a mixture layer of Tb 2 O 3 and Tb--Si--O depending on the annealing temperature.