Crack-free GaN/Si(111) epitaxial layers grown with InAlGaN alloy as compliant interlayer by metalorganic chemical vapor deposition

A new method is demonstrated to be effective in reducing mismatch-induced tensile stress and suppressing the formation of cracks by inserting InAlGaN interlayers during the growth of GaN upon Si (1 1 1) substrate. Compared with GaN film without quaternary interlayer, GaN layer grown on InAlGaN compliant layers shows a five times brighter integrated PL intensity and a (0 0 0 2) High-resolution X-ray diffraction (HRXRD) curve width of 18 arcmin. Its chi(min), derived from Rutherford backscattering spectrometry (RBS), is about 2.0%, which means that the crystalline quality of this layer is very good. Quaternary InAlGaN layers, which are used as buffer layers firstly, can play a compliant role to endure the large mismatch-induced stress and reduce cracks during the growth of GaN epitaxy. The mechanisms leading to crack density reduction are investigated and results show that the phase immiscibility and the weak In-N bond make interlayer to offer tenability in the lattice parameters and release the thermal stress. (c) 2005 Elsevier B.V. All rights reserved.

Strain relaxation of InP film directly grown on GaAs patterned compliant substrate

In order to overcome the large lattice mismatch in the heteroepitaxy, a new patterned compliant substrate method has been introduced, which has overcome the disadvantages of previously published methods. InP film of thickness 800 nm was directly grown on this substrate. Scanning electron microscopy (SEM) has shown that good surface morphology has been obtained. In addition, Photoluminescence (PL) and double crystal X-ray diffraction (DCXRD) study have shown that the residual strain has been reduced, and that the structure quality has been improved. (C) 2002 Elsevier Science B.V. All rights reserved.

On-Chip All-Optical Passive 3.55 Gbit/s NRZ-to-PRZ Format Conversion Using a High-Q Silicon-Based Microring Resonator

We report the experimental result of all-optical passive 3.55 Gbit/s non-return-to-zero (NRZ) to pseudo-return-to-zero (PRZ) format conversion using a high-quality-factor (Q-factor) silicon-based microring resonator notch filter on chip. The silicon-based microring resonator has 23800 Q-factor and 22 dB extinction ratio (ER), and the PRZ signals has about 108 ps width and 4.98 dB ER.