The inter-sub-level transitions in modulation-doped Ge quantum dots are observed. The dot structure is grown by molecular-beam epitaxy, and consists of 30 periods of Ge quantum dots sandwiched by two 6 nm boron-doped Si layers. An absorption peak in the midinfrared range is observed at room temperature by Fourier transform infrared spectroscopy, which is attributed to the transitions between th...

the aim of this research is studying the effects of ge-doped on co adsorption on the outer and inner surfaces of (6, 0) zigzag model of boron nitride nanotube (bnnts) by using dft theory. for this purpose, eight models of co adsorption on the surfaces of bnnts are considered. at first step, all structures were optimized at b3lyp and 6-31g (d) standard base set and then the electronic structure,...

Hydrogen interstitials-mediated ferromagnetism in MnxGe1−x magnetic semiconductors was studied by first-principles calculations. It was found that the H:1s state in Mn–H–Mn complexes can strongly hybridize with the valence states of Mn and change the spin polarization of Mn atoms. Although the dopedMn atoms tend to form the nearest-neighborMn atomic pairs with antiferromagnetic coupling in Mn-d...

This paper describes a preliminary study of the thermoluminescence (TL) response of doped SiO(2) optical fibres subjected to (241)AmBe neutron irradiation. The TL materials, which comprise Al- and Ge-doped silica fibres, were exposed in close contact with the (241)AmBe source to obtain fast neutron interactions through use of measurements obtained with and without a Cd filter (the filter being ...

Exchange-constants have been evaluated from first-principles in Mn-doped Ge, mainly focusing on the effects of the impurity concentration and of the arrangement of Mn-atoms in the semiconducting matrix. As expected, the Mn-concentration strongly affects the magnitude of the exchange constants (especially between Mn as first-nearest-neighbors (NNs) in the cation position). Interestingly, the arr...

A key milestone for the next generation of high-performance multifunctional microelectronic devices is the monolithic integration of high-mobility materials with Si technology. The use of Ge instead of Si as a basic material in nanoelectronics would need homogeneous p- and n-type doping with high carrier densities. Here we use ion implantation followed by rear side flash-lamp annealing (r-FLA) ...

The codiffusion of Ge with dopant atoms ~boron or arsenic! into Si substrates is analyzed using secondary ion mass spectroscopy. While earlier studies have focused on the diffusion of dopants across deposited Si12xGex films or on diffusion phenomena at in situ doped Si12xGex /Si interfaces, this paper reports on the codiffusion of Ge and implanted dopant atoms into Si substrates resulting in th...

Monte Carlo simulation of carrier dynamics and far-infrared absorption in a selectively-doped p-type multilayer Ge structure with vertical transport was performed to test a novel terahertz laser concept. The design exploits the known mechanism of THz amplification on intersubband transitions in p-Ge, but with spatial separation of light hole accumulation regions from doped regions, which allows...

The 3 862.5 cm−1 vibration of oxygen in crystalline germanium is shown to decay into one 1 local mode of the oxygen center plus two lattice modes. This description predicts increases in the linewidths in O-doped germanium, and decreases in the linewidths in O-doped germanium, as the Ge mass in the Ge-O-Ge complex increases, in agreement with observation. The decay time is expected to vary only ...

Diluted ferromagnetic semiconductors (FMS) are in the focus of intense research due to their potential applications in spintronics and their striking new physical properties. So far Mn-doped III-V compound semiconductors such as GaMnAs are the most important and best understood ones, but they are ferromagnetic only at well below room temperature. An interesting alternative could be magnetic sem...