Efficient rainbow color luminescence from In_xGa_(1-x)N single quantum wells fabricated on {1122} microfacets

摘要

Rainbow color luminescence from In_xGa_(1-x)N single quantum wells (SQWs) is achieved and almost covers the entire visible range when the layers are fabricated on {1122} facets with a few micron-width using a regrowth technique on striped GaN templates. These facets are tilted 56° with respect to the (0001) facets and border the (0001) and {1120} facets. The emission wavelength on the {1122} facets is redshifted from the {1120} side to (0001) side due to the variations of the In composition, which leads to the color contrast with the rainbow geometry. The temperature dependence of the photoluminescence intensity shows that the internal quantum efficiency at room temperature is 33% due to the very small internal electric fields and a small threading dislocation density compared to that in conventional (0001) In_xGa_(1-x)N SQWs. Since the emission efficiency does not show a noticeable emission wavelength dependence, this type of structure has potential as light-emitting devices with multiwavelengths that perform numerous color controllability such as pastel and white colors.