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Herein, the carrier lifetime in approximately 5x10^16 cm^(-3) n-doped In(x)Ga(1-x)As layers is studied by diode current–voltage analysis and by time-resolved photoluminescence. Two sets of hetero-epitaxial layers are grown on semi-insulating InP or GaAs substrates. The first set corresponds with a constant In content p + n stack, while the second set has a fixed x = 0.53 for the n-layer, while containing various extended defect densities by using a strain relaxed buffer with different x. This results in threading dislocation densities (TDDs) between approximately 10^5 cm^(-2) and a few 10^9 cm^(-2). It is shown that the overall trend of the recombination lifetime versus TDD can be described by a first-order model considering a finite recombination lifetime value inside a dislocation core of 1 nm. For the generation lifetime, a strong electric-field enhancement factor is found. Also, the residual strain in the n-layer has an impact. Overall, the safe limit for TDD depends on the type of application and on the operation conditions (reverse diode bias).

The observation and interpretation of Frank stacking faults, Shockley stacking faults, Lomer dislocations, and 60 degrees misfit dislocations, which have similar line shapes in the (001) In0.53Ga0.47As crystalline surface, are performed with the electron channeling contrast imaging (ECCI) technique. To minimize the backscattered electron (BSE) contrast that resulted from the surface morphology, a relatively flat region is first selected and compared with an atomic force microscopy (AFM) image and then, subsequently, examining ECCI with transmission electron microscopy (TEM)-like invisibility criteria. By orthogonally choosing the diffraction vector g between (220) and (2-20), misfit dislocations seem to be always visible but partially faint in the g parallel to the line direction on the surface. With respect to the image contrast, Frank stacking faults and Lomer dislocations are likely to be completely invisible for parallel g. The criteria are further confirmed by cross-sectional TEM analysis, which shows a preferred homogeneous surface nucleation.

Silicon does not emit light efficiently, therefore the integration of other light-emitting materials is highly demanded for silicon photonic integrated circuits. A number of integration approaches have been extensively explored in the past decade. Here, the most recent progress in this field is reviewed, covering the integration approaches of III-V-to-silicon bonding, transfer printing, epitaxial growth and the use of colloidal quantum dots. The basic approaches to create waveguide-coupled on-chip light sources for different application scenarios are discussed, both for silicon and silicon nitride based waveguides. A selection of recent representative device demonstrations is presented, including high speed DFB lasers, ultra-dense comb lasers, short (850nm) and long (2.3 mu m) wavelength lasers, wide-band LEDs, monolithic O-band lasers and micro-disk lasers operating in the visible. The challenges and opportunities of these approaches are discussed.