Hydrogenated amorphous silicon carbide alternating-current thin-film light-emitting diodes (a-SiC:H ACTFLEDs) have been successfully fabricated on indium-tin-oxide-coated glass substrates and characterized. The electroluminescence (EL) spectra of an obtained ACTFLED under either a dc (positive or negative) bias or a sinusoidal ac voltage were qualitatively very similar, with a peak wavelength at about 655 nm and a shoulder at about 620 nm. The EL threshold voltage and brightness of the ACTFLEDs were sensitive to the contact behavior between the metal electrode employed and amorphous film. Moreover, the EL intensity of an ACTFLED increased with the frequency up to 500 kHz and then decreased rapidly and became very weak as the frequency increased to about 1 MHz. A model based on the equivalent circuit has also been proposed to explain this frequency-dependent EL behavior. (c) 2007 The Electrochemical Society.