An LED is provided comprising two or more light-emitting Type II
interfaces wherein at least two of the Type II interfaces differ in
transition energy by at least 5%, or more typically by at least 10%, and
wherein at least one of the Type II interfaces is within a pn junction.
Alternately, an LED is provided comprising two or more light-emitting
Type II interfaces wherein at least two of the Type II interfaces differ
in transition energy by at least 5%, or more typically by at least 10%.
The Type II interfaces may include interfaces from a layer which is an
electron quantum well and not a hole quantum well, interfaces to a layer
which is a hole quantum well and not an electron quantum well; and
interfaces that satisfy both conditions simultaneously. The Type II
interfaces may be within a pn or pin junction or not within a pn or pin
junction. In the later case, emission from the Type II interfaces may be
photopumped by a nearby light source. The LED may be a white or
near-white light LED. In addition, graphic display devices and
illumination devices comprising the semiconductor device according to the
present invention are provided.