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Recent Developments in InGaN-Based Blue Leds and Lds

100%

Nakamura S.

Acta Physica Polonica A

1999

vol. 95

issue 1

153-164

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.

Body weight of high and low aggression mice under various population densities

45%

Oikawa T., Kawamoto Y., Nakamura S., Morimasa T., Sato K.

Journal of Applied Genetics

2000

vol. 41

issue 1

35-42

The body weight of 21st generation mice selected divergently according to their aggression was compared in different population densities. The mice under isolated housing demonstrated higher levels of aggression in both lines. The growth of the mice was similar among the groups of different population densities in both lines. Only the males of the high aggression line showed a large phenotypic variance in the medium and high population densities, whereas no differences were observed among the population densities in males of the low aggression line or in the females of both lines. Our study suggested that the aggression of males was a source of extra variance in the high population density, resulting in heterogeneity of variance and genotype by sex interaction.

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1 Acta Physica Polonica A

1 Journal of Applied Genetics

1 2000

1 1999

2 Nakamura S.

1 Kawamoto Y.

1 Morimasa T.

1 Oikawa T.

1 Sato K.

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Recent Developments in InGaN-Based Blue Leds and Lds

Body weight of high and low aggression mice under various population densities