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The effects of InGaAs/GaNAs barrier combinations were investigated in the metal organic vapor phase epitaxy grown GaInNAs quantum wells (QWs). Significant improvement was made in the optical performance of the 1.3 μm range with the proposed structures. Structural investigation linked with the optical properties reveals that a thin InGaAs layer, placed between GaInNAs QWs and GaNAs layers, plays a role in redistributing the nitrogen within the QWs while maintaining a sharp interface. The amount of diffused nitrogen is proportional to the strain residing in the InGaAs layer, which explains the tendency of blueshift with the increase in GaNAs thickness. [ABSTRACT FROM AUTHOR]

The authors analyzed radiative efficiency of InGaN laser diodes (LDs) emitting at 405 nm. Based on semiconductor rate equations, the radiative efficiency is unambiguously determined by the analysis of electroluminescence characteristics. The radiative efficiency exceeds 70% even far below threshold of ∼3 mA at a high temperature of 80 °C. This highly radiative characteristic is attributed to reduced contribution of nonradiative recombination in LDs with low-dislocation-density active material. It is also found that the radiative efficiency is almost independent of threshold current, indicating that nonradiative recombination is not a major factor which determines lasing threshold in 405 nm emitting InGaN LDs having low dislocation density. [ABSTRACT FROM AUTHOR]

We report a high power fundamental transverse mode operation of an optically pumped 1060 nm vertical-external-cavity surface-emitting laser. A diamond heat spreader was capillary bonded to the semiconductor surface. A 10 W continuous wave operation with optical-to-optical conversion efficiency of 44% was achieved at room temperature. The thermal rollover was not found up to a heat sink temperature of 60 °C. High efficiency and good thermal stability were mainly due to the optimization of epitaxial quality and the high conductivity of the diamond heat spreader. We have found that the increase of the round trip loss caused by the heat spreader was about 1%. [ABSTRACT FROM AUTHOR]