InGaN/GaN quantum dot visible lasers

The demonstration of quantum dots (QDs) with emission covering the entire visible spectrum is important for many applications including solid-state lighting [1,2]. Current white light-emitting diodes typically incorporate blue-emitting InGaN/GaN quantum wells and rely on a phosphor to convert some of the blue light to yellow or red. Tuning of the white emission requires the development of new phosphors with the desired emission characteristics. Alternatively, electrically injected devices incorporating blue and red-emitting QDs can be used to directly generate red light, which is tunable by simply changing the indium composition in the dots. Such light-emitting diodes (LEDs) and lasers are also important for display and mobile projector applications, which require blue-, green-, and red-emitting devices [1,2]. InGaN-based QDs may be used for all these wavelengths, negating the need for the use of multiple material systems in these applications. Blue- and green-emitting lasers can be realized with InGaN/GaN-based single or multiple quantum wells [3-10], but red-emitting lasers are typically fabricated using other material systems [11,12] as red-emitting InGaN/GaN quantum well (QW) lasers have yet to be reported.