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

Abstract

Current–voltage (I G–V G) 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. I G 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 5D4–7F J (J = 6, 5, 4, and 3) of Tb3+ ions and 5D0–7F J (J = 1, 2, 3, and 4) of Eu3+ ions, respectively. EL intensity increased proportionally to I G 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.

Ultraviolet and white electroluminescence from metal–oxide–semiconductor devices fabricated by spin-coating of gadolinium organic compounds on silicon

“…The fabrication procedures were the same as those in our previous experiments. 26,27) The surface color of all devices after the annealing treatments was yellowish white.…”

“…The EL spectrum of wavelengths ranging from 290 to 1000 nm can be detected at once with the resolution of 1.2 nm/pixel, where the wavelength range was improved from the previous setup. 26,27) The exposure time of the CCD camera for EL spectrum measurements was varied from 1 to 10 s depending on the measured I G . ), the rising voltages +V R , at which +I G increased steeply, were about +11 and +13 V, respectively.…”

“…25) These results described above suggest that a silicate film doped with rare-earth elements has the capability of EL emission. MOS devices with terbium-silicate-related oxide (Tb-Si-O) were fabricated by furnace annealing of Tb/(Tb + Ba) and (Tb + Eu) organic compound films, which had been spin-coated on the n + -Si substrate, and showed the radiation of green and red EL, 26,27) respectively. MOS devices with other rare-earth elements, which may have different spectrum peaks, are candidates for multicolor EL devices.…”

UV and Visible range Electroluminescence from MOS Devices Fabricated by Spin-Coating of Gd/Dy Organic Compound Films on Silicon

“…The EL spectra were measured by a back-illuminated CCD camera stabilized at -70 °C with a monochromator under a constant current supply. The wavelength range from 290 to 1000 nm can be detected at once [3,4]. Fig.…”

“…Recently, EL in ultraviolet (UV) through IR range from MOS devices with rare-earth elements were reported [1,2]. MOS devices fabricated with the spin-coated organic compound films of Tb/Eu showed the green and red EL [3,4].…”