Image Number 4 for United States Patent #8148742.
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.
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