The effect of optical excitation conditions on the spectral and temporal characteristics of the radiation from two-dimensional photonic crystals based on the structures with self-assembled Ge(Si) nanoislands has been studied. It was shown that one of the main factors effecting the spectral position and shape of photoluminescence lines, as well as the photoluminescence kinetics of photonic crystals with Ge(Si) nanoislands, along with the mode structure of the photonic crystal, are the local heating of the samples and the concentration of nonequilibrium charge carriers created by the absorption of the pumping radiation.

Two-dimensional Si-based photonic crystals with embedded Ge nanoislands were studied. In particular, dependences of the steady-state and time-resolved photoluminescence response on the depth of the air-holes which form the photonic crystal itself were investigated. It was shown that the maximum luminescence intensity was observed not for the fully-etched photonic crystals but for the intermediately etched ones. The possible origin of such a behavior is discussed.

In this work formation of locally strained Ge structures on SOI substrates is reported and their optical properties are discussed. Suspended Ge structures were fabricated by optical lithography, plasmachemical and wet chemical etching using the “stress concentration” approach. The fabrication procedure of suspended structures were modified in such a way to provide the mechanical contact between them and the underlying layers so improving the heat dissipation from them. SOI substrates with top Si layer being only 100 nm thick were utilized in such fabrication scheme. The decrease of local heating in such kind of structures was confirmed by the study of micro-Raman scattering depending of scanning laser power. Micro-photoluminescence measurements have shown the remarkable enhancement of the integrated intensity from locally strained areas of a microstructure. It was also shown that structures brought in contact with underlying layers could sustain much higher pumping power densities without fracture as compared to the suspended ones.

In this work, formation of locally tensile strained Ge structures (micro-bridges) on SOI substrates embedded into microcavities is reported and their optical properties are discussed. The cavity compatible with the shape of the active region was designed in such a way as to provide an effective localization of the electromagnetic field in the active region of the structure, as well as to minimize the strain redistribution due to the cavity formation. Micro-photoluminescence (PL) studies have shown a remarkable enhancement of the PL intensity for the locally strained areas as compared to the initial Ge film. It was shown that the formation of a microcavity leads to a decrease in the maximum strain in the active region of the structure, but provides an overall increase in the PL intensity.