Green/Red Electroluminescence from Metal–Oxide–Semiconductor Devices Fabricated by Spin-Coating of Rare-Earth Organic Compounds on Silicon

Abstract

Current–voltage (IG–VG) characteristics and green/red electroluminescence (EL) from metal–oxide–semiconductor (MOS) devices with indium–tin oxide (ITO)/[(Tb/Ba–Si–O)/(Tb/Eu–Si–O)] layers/n+-Si substrate are reported. The (Tb/Ba–Si–O) and (Tb/Eu–Si–O) layers were fabricated from the mixtures of organic liquid sources of (Tb+Ba) and (Tb+Eu), respectively, which were spin-coated on the n+-Si substrate and annealed at 850 °C for 30 min in air. IG currents under EL emission correspond to Fowler–Nordheim (FN) tunnel current. The MOS devices with the (Tb/Ba)–Si–O layer and the (Tb/Eu)–Si–O layer emitted green and red EL, which originated from the intrashell transitions of 5D4–7FJ (J = 6, 5, 4, and 3) of Tb3+ ions and 5D0–7FJ (J = 1, 2, 3, and 4) of Eu3+ ions, respectively. EL intensity increased proportionally to IG to the n-th power, where n was about 1.3, and the EL spectra were independent of the currents. The oxide layers on the Si substrate for the green and the red devices have the total thicknesses of about 40 and 30 nm, which consist of [Tb2O3 and (Tb/Ba–Si–O)] and [Tb2O3/Eu2O3 and (Tb/Eu–Si–O)] mixtures, respectively.