Investigation of Chirped Well Structures for Broad-Spectrum AlGaInP-Based Light Emitting Diodes.

We investigated broad-spectrum light emitting diodes appropriate for special lighting applications in terms of their optical behaviors and device performances according to the chirped multi-quantum well structures. As the well thickness was increased from 6 to 15 nm, the electroluminescent spectrum was broadened by 43%, the forward bias voltage was lowered by 7% and the light output power was showed similar values in comparison to light emitting diodes having conventional multiquantum well structures. In the case of the chirped multi-quantum well structures having sequentially decreasing the well thickness from 15 nm to 6 nm, the optical output power was decreased by 38% due to the spreading problems of holes into the n -side active region.