III-nitride LEDs Research Articles

High-performance III-nitride blue LEDs grown and fabricated on patterned Si substrates

InGaN/GaN based blue LEDs with 2-μm-thick crack-free GaN buffer layers were successfully grown and fabricated on patterned Si (1 1 1) substrates. The patterns on the substrates include 340 μm×340 μm square islands, separated by 3-μm deep and 20 μm wide trenches, along the 〈 1 l ¯ 0 〉 and 〈 1 1 2 ¯ 〉 crystalline orientations. In addition to using the patterned growth technique, thin AlN and SiN x interlayers grown at high temperatures were also employed to partially release the residual stress and to further improve the crystalline quality. Blue LEDs of 300×300 μm 2 fabricated on the islands, without thinning and packaging, exhibited a high output power of around 0.7 mW at a drive current of 20 mA. Compared to III-nitride LEDs grown on sapphire substrates, the same LED structures grown on patterned Si substrates showed a few nm of red shift in emitting wavelength, suggesting some residual stress of GaN on patterned Si.

Investigation of Structural and Optical Properties of III-Nitride LED grown on Patterned Substrate by MOCVD

Investigation of Structural and Optical Properties of III-Nitride LED grown on Patterned Substrate by MOCVD

Simulation of visible and ultra-violet group-III nitride light emitting diodes

One-dimensional drift-diffusion model accounting for the unique properties of group-III nitrides is employed to simulate the carrier transport and radiative/non-radiative recombination of electrons and holes in light emitting diode heterostructures. Mixed finite-element method is used for numerical implementation of the model. The emission spectra are computed via the self-consistent solution of the Schrödinger–Poisson equations with account of complex valence band structure of nitride materials. Simulations of a number of single- and multiple-quantum well blue and ultraviolet light emitting diodes are presented and compared with available observations. Specific features of the III-nitride LED operation are considered in terms of modelling. Applicability of the drift-diffusion model to analysis of III-nitride LEDs is proved and still open questions are discussed.