Thermal structuring of metal-semiconductor core fibres: toward optoelectronic device fabrication

Combining metal and semiconducting components in the core of a glass-clad fibre brings new breadth to the range of structures that can be fabricated using localized thermal gradients. Both axial and lateral structuring of fibres drawn withm ultiple components is demonstrated, as well as the introduction, segregation and chemical reaction of metal components within an initially pure silicon core. Gold and tin longitudinal electrodes fabrication, segregation of GaSb and Si in an initially inhomogeneous fiber into parallel axial layers and Al doping of a GaSb core were demonstrated. Gold was introduced into Si fibers to purify the core or weld an exposed core to a Si wafer. Ga and Sb introduced from opposite ends of a silicon fibre reacted to form III-V GaSb within the Group IV Si host, as confirmed by structural and chemical analysis and room temperature photoluminescence.

Enhancing the photoluminescence response from thick Ge-on-Si layers using the photonic crystals

More than an order of magnitude enhancement of the room-temperature photoluminescence (PL) signal from rather thick Ge layers grown on Si(001) was obtained by utilization of the two-dimensional photonic crystals (PhC). A set of PhCs with different periods and filling factors was fabricated and studied using a micro-PL spectroscopy. Optical features of the fabricated PhCs were also theoretically modeled using a rigorously coupled wave analysis which allowed to bring the observed peaks in the PL response into correlation with the different modes of PhC. In particular, we were able to associate the well-resolved peaks in the PL spectra with the optically active modes of the PhCs. The obtained results proved the possibility of using a homogeneously distributed active medium in PhCs without the formation of specially designed cavities in order to redistribute the internal emitted light into the required modes and efficiently extract it to the far field. The relative simplicity and higher tolerance to fabrication imperfections, as well as the large working area of such kind of PhCs as compared to PhCs with microcavities can be advantageous for creating a PhC-based Si-compatible light source for the telecom band.