A green light-emitting diode ͑LED͒ was fabricated using self-assembled In-rich InGaN quantum dots ͑QDs͒. The photoluminescence studies showed that the QDs provide thermally stable deeply localized recombination sites for carriers with negligibly small piezoelectric field. The electroluminescence spectra of the LED showed a peak in the green spectral range and the dominant peak was blueshifted with increasing injection current due to the distribution of depth of the potential wells of QDs. The output power of the LED increased with increasing injection current, indicating that the potential wells are thermally stable and deeply localized in the QDs.

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We report on the effect of the position of the Si delta-doped layer within a GaN barrier layer on the optical properties of a InGaN∕GaN single quantum well (SQW) with an emission wavelength of 374nm. When the Si delta-doped layer was very close to the SQW layer, the potential well of the Si delta-doped layer overlapped the SQW potential, reducing photoluminescence (PL) intensity. When the Si delta-doped layer was very far away from the SQW layer, carrier injection from the Si delta-doped layer into the SQW layer was not observed. However, the Si delta-doped layer located 12nm away from the SQW layer showed enhanced PL intensity due to effective electron injection from the Si delta-doped layer into the SQW layer and to an increase in hole confinement in the valence band.