Luminescence-current characteristics and temperature influence on luminescence of a-SiC thin.film light-emitting diodes fabricated by RF-PECVD methed have been measured clearly.Under direct current conditions

the luminescence of the devices goes to saturation at about 1A/cm

2

current density;and under pulsed current with low duty ratio

it grows with current density near-linearly up to 20A/cm

2

and with increasing of circumstance temperture

the luminescence decreases rapidly.After analyszing the devices in heated state

it is shown that temperature-quenching

instead of field-quenching

leads to luminescence saturaiton of the devices at high current

and at last some methods of improving heat dissipation of the device are proposed briefly.