Recent Developments in InGaN-Based Blue Leds and Lds
S. Nakamura
Department of Research and Development, Nichia Chemical Industries, Ltd., 491 Oka, Kaminaka, Anan, Tokushima 774, Japan
Full Text PDF
UV/blue/green/amber InGaN quantum-well structure light-emitting diodes with an external quantum efficiency of 7.5%, 11.2%, 11.6%, and 3.3% were developed. The localization in the InGaN well layer induced by the In composition fluctuations seems to be a key role of the high efficiency of those InGaN-based light-emitting diodes. When the electrons and holes are injected into the InGaN active layer of the light-emitting diodes, these carriers are captured by the localized energy states before they are captured by the nonradiative recombination centers caused by the large number of threading dislocations. InGaN multi-quantum-well structure laser diodes with modulation doped strained-layer superlattice cladding layers grown on the epitaxially lateral overgrown GaN substrate were demonstrated to have an estimated lifetime of more than 10000 hours under room temperature continuouswave operation. When the laser diode was formed on the GaN layer above the SiO_2 mask region without any threading dislodations, the threshold current density was as low as 2.7 kA cm-2. When the laser diode was formed on the window region with the high threading dislocation density, the threshold current density was as high as 4.5 to 9 kA cm-2. A leakage current due to a large number of threading dislocations caused the high threshold current density on the window region.
DOI: 10.12693/APhysPolA.95.153
PACS numbers: 68. 55.Ce, 72.80.Ey, 73.60.Br, 71.55.Eq