Wafer-scale detachable monocrystalline germanium nanomembranes for the growth of III-V materials and substrate reuse.

Germanium (Ge) is increasingly used as a substrate for high-performance optoelectronics, photovoltaics, and electronic devices. These devices are usually grown on thick and rigid Ge substrates manufactured by classical wafering techniques. Nanomembranes (NMs) provide an alternative to this approach while offering wafer-scale lateral dimensions, weight reduction, waste limitation, and cost effectiveness.

Defect free strain relaxation of microcrystals on mesoporous patterned silicon.

A perfectly compliant substrate would allow the monolithic integration of high-quality semiconductor materials such as Ge and III-V on Silicon (Si) substrate, enabling novel functionalities on the well-established low-cost Si technology platform. Here, we demonstrate a compliant Si substrate allowing defect-free epitaxial growth of lattice mismatched materials. The method is based on the deep patterning of the Si substrate to form micrometer-scale pillars and subsequent electrochemical porosification.

In-Situ Transmission Electron Microscopy Observation of Germanium Growth on Freestanding Graphene: Unfolding Mechanism of 3D Crystal Growth During Van der Waals Epitaxy.

Breakthroughs in cutting-edge research fields such as hetero-integration of materials and the development of quantum devices are heavily bound to the control of misfit strain during heteroepitaxy. While remote epitaxy offers one of the most intriguing avenues, demonstrations of functional hybrid heterostructures are hardly possible without a deep understanding of the nucleation and growth kinetics of 3D crystals on graphene and their mutual interactions. Here, the kinetics of such processes from real-time observations of germanium (Ge) growth on freestanding single layer graphene (SLG) using in-situ transmission electron microscopy are unraveled.

Ultrafast photocarrier dynamics in Fe-implanted InGaAs polycrystalline photoconductive materials.

We investigate the ultrafast photoconductivity and charge-carrier transport in thermally annealed Fe-implanted InGaAs/InP films using time-resolved terahertz spectroscopy. The samples were fabricated from crystalline InGaAs films amorphized with Fe ions implantation. The rapid thermal annealing of the InGaAs layer induces solid recrystallization through the formation of polycrystalline grains whose sizes are shown to increase with increasing annealing temperature within the 300-700 °C range.

Probing the coupling between the components in a graphene-mesoporous germanium nanocomposite using high-pressure Raman spectroscopy.

The nature of the interface between the components of a nanocomposite is a major determining factor in the resulting properties. Using a graphene-mesoporous germanium nanocomposite with a core-shell structure as a template for complex graphene-based nanocomposites, an approach to quantify the interactions between the graphene coating and the component materials is proposed. By monitoring the pressure-induced shift of the Raman G-peak, the degree of coupling between the components, a parameter that is critical in determining the properties of a nanocomposite, can be evaluated.