Active region based on graded-gap InGaN/GaN superlattices for high-power 440- to 470-nm light-emitting diodes.

The structural and optical properties of light-emitting diode structures with an active region based on ultrathin InGaN quantum wells limited by short-period InGaN/GaN superlattices from both sides have been investigated. The dependences of the external quantum efficiency on the active region design are analyzed. It is shown that the use of InGaN/GaN structures as limiting graded-gap short-period superlattices may significantly increase the quantum efficiency. [ABSTRACT FROM AUTHOR]