A 0.85μm-thick n+-GaN:Si epitaxial layer inserted between InGaN light-emitting diodes (LEDs) structure and sapphire substrate that was transformed into the nano-pipe structure in wet etching process. The directional nano-pipe (NP) structure was perpendicular to the laser scribing lines and guided by the external bias electric field. Wide etching width (560μm) and high lateral etching rate (9.3μm/min) were achieved in the middle size of InGaN LED chip (560×910 μm2). High light output power and slightly Fabry-Pérot interferences were observed in the treated LED structure which caused by low effective refractive index in the NP-GaN structure.

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The cavity gain of InGaN laser diode is simulated and optimized. The optimized QW number of LD is suggested to be 2 due to imbalance of carrier injection. We also find by tuning the refractive index of the AlGaN cladding layer can make the higher Gamma and can also to enhance the gain peak

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The carrier transport in the V-pit structures has been modeled. The V-shaped pit provides another lateral path for carriers flowing to the deeper quantum wells (QWs) by the (1101) sidewalls. The radiative recombination rate is high in middle QWs. The turn-on voltage is much lower with existence of V-pits.

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In this paper, a new phosphor modeling algorithm with thermal prediction is proposed and demonstrated. Different pumping blue dice are conducted to figure out the redshift effect in blue LEDs. Also, the phosphor degradation is taken into account to make the phosphor model with modified absorption coefficients and conversion efficiencies to have a chromatic prediction with thermal effect under 0.02.

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GaN epi-layer suffers from a high threading dislocation density due to their lattice mismatch and thermal coefficient misfit. In this work, the aluminium nitride (AlN) nanorod templates were grown on the sapphire substrate by VLS mechanism to improve the crystalline quality of GaN epi-layer.

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