LIGHT EMITTING TRANSISTOR
A light emitting transistor (LEFET) which is a light emitting element having a switching function, can produce a sufficient light emission intensity, and is formed to provide a higher light emission efficiency. Aluminum is used as the material of a drain electrode (25), and gold is used as the material of a source electrode (24). When a voltage is applied to between the source electrode (24) and the drain electrode (25), holes are injected from the source electrode (24) and electrons are injected from the drain electrode (25) respectively into a light emitting layer (26). Holes and electrons are re- coupled, and then the light emitting layer (26) emits light. The turning on/off of light emission is controlled by turning on/off a gate voltage.
Unlike a conventional technique of using gold for a drain electrode, this invention uses aluminum having a smaller work function than gold so that more electrons can be injected into the light emitting layer (26) at a lower voltage. Accordingly, light emission intensity and efficiency are improved.