Plasma composition by mass spectroscopy in a Ar-SiH4-H 2 LEPECVD process during nc-Si deposition

Plasma composition by mass spectroscopy in a Ar-SiH4-H 2 LEPECVD process during nc-Si depositio

Spin polarized photoemission from strained Ge epilayers grown by low-energy plasma-enhanced CVD (LEPECVD)

Spin polarized photoemission from strained Ge epilayers grown by low-energy plasma-enhanced CVD (LEPECVD

Hydrogenated nanocrystalline silicon thin films studied by scanning force microscopy.

Abstract. Hydrogenated nanocrystalline silicon for photovoltaic applications has been investigated. Morphological properties, as well as electrical properties, have been investigated with high spatial resolution by scanning force microscopy analyses (AFM, Atomic Force Microscopy and C-AFM conductive AFM). A major problem regarding the electronic properties is to understand where the current flows. The present contribution aims to clarify which of the material phases mainly contributes to the conduction mechanism

Low thermal budget fabrication of III-V quantum nanostructures on Si substrates

Low thermal budget fabrication of III-V quantum nanostructures on Si substrate

Raman efficiency in SiGe alloys

Raman spectroscopy is commonly used for the optical characterization of structural properties of SiGe alloys, but a measurement of the Raman efficiency as a function of excitation wavelength and concentration is still lacking. This information is nevertheless important for the interpretation of data, especially for the analysis of inhomogeneous samples. In this work, the relative Raman efficiency of Si1−xGex alloys has been obtained for several excitation energies as a function of the composition x with steps of x = 0.02 across the whole composition range. We observed resonances in correspondence of the E1 / E1+1 and E0 / E0+0 transitions. For a fixed excitation energy the efficiency varies of about two orders of magnitude vs. the composition of the alloy, while, for a fixed composition, we observed a change in efficiency of up to three orders of magnitude depending on the excitation energy. The maximum scattering efficiency at resonance decreases by an order of magnitude when moving from silicon-rich to germanium-rich alloys. The data are discussed in terms of the polarizability and compared to the literature relative to pure silicon and germanium. The data reported in this paper can be used to design experiments under resonant conditions to selectively probe different regions in inhomogeneous samples

Photoluminescence and ultrafast intersubband relaxation in Ge/SiGe multiple quantum wells

Photoluminescence and ultrafast intersubband relaxation in Ge/SiGe multiple quantum well

Giant AC Stark shift in germanium

Giant AC Stark shift in germaniu

Optical spin injection in SiGe heterostructures

Optical spin injection in SiGe heterostructure

Comparison of ultrafast carrier thermalization in Gaxln1-xAs and Ge quantum wells

The thermalization of photoexcited carriers is investigated using femtosecond pump-probe spectroscopy in both (GaIn)As and Ge quantum wells. In both materials a nonthermal electron distribution is observed. The continuous relaxation from the point of injection toward the ground state and the thermalization of the carrier distribution are monitored on a time scale of up to 500 fs at room temperature. Carriers in (GaIn)As thermalize within 300 fs when injected with an excess energy of 250 meV. Separate carrier distributions for the heavy-hole and light-hole systems are found since the angular momentum transfer required for a transition is slow. Thermalization in Ge is found to be slightly slower in comparison due to the lack of Fröhlich interaction

Polarization dependence of quantum-confined Stark effect in Ge/SiGe quantum well planar waveguides

Polarization dependence of quantum-confined Stark effect in Ge/SiGe quantum well planar waveguide