White electroluminescence (EL) was observed for the first time in the hydrogenated amorphous silicon‐carbon alloy a
=0.2–0.4) at room temperature. Experiments were carried out for the devices which consisted of an amorphous film sandwiched between two insulating layers of Y2
. EL is observable above a threshold ac voltage of 100 V. The EL spectrum is slightly different from the photoluminescence spectrum of the amorphous film.