Dopant concentration; Half-metal; Spin polarization; Graphene Abstract The singly B and N doped graphene systems are carefully studied. The highly concentrated dopants cause a spin polarization effect in the systems. The spin polarization limits are affirmed in the singly B and N doped graphene systems through periodic hybrid density functional theory studies. The spin polarization effects must...

Li-Yb co-doped nano-crystalline ZnO has been synthesized by a method of thermal growth from the salt mixtures. X-ray diffraction, transmission electron microscopy, atomic absorption spectroscopy and optical spectroscopy confirm the doping and indicate that the dopants may form Li-Li and Yb(3+)-Li based nanoclusters. When pumped into the conduction and exciton absorption bands of ZnO between 250...

Vertical arrays of single walled carbon nanotubes (VA-SWNTs) were grown using bi-metallic nanoparticle pro-catalysts. Iron oxide particles were doped with varying quantities of first row transition metals (Mn, Co, Ni, and Cu) for a comparative study of the growth of nanotubes. VA-CNT samples were verified using scanning electron microscopy, and characterized using resonance Raman spectroscopy. ...

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...

Sustainable future energy scenarios require significant efficiency improvements in both electricity generation and storage. High-temperature solid oxide cells, and in particular carbon dioxide electrolysers, afford chemical storage of available electricity that can both stabilize and extend the utilization of renewables. Here we present a double doping strategy to facilitate CO2 reduction at pe...

There are many interests to achieve long-range magnetic order in topological insulators of Bi2Se3 or Bi2Te3 by doping magnetic transition metals such as Fe and Mn. The transition metals act as not only magnetic dopants but also electric dopants because they are usually divalent. However, if the doping elements are rare-earth metals such as Gd, which are trivalent, only magnetic moments can be i...

A static plasma grating has been demonstrated experimentally [l] in a large optical cavity FIB-DBR GaAIAs/GaAs laser diode. The grating is formed by implanting stripes of dopants with a focused ion beam (FIB). The dopants ionize to form periodic fluctuations in the carrier concentration which, through the Kramers-Kronig relations, form an index grating. A model of the grating strength for optim...

Photoluminescence ~PL! from the recombination of excitons bound to isoelectronic Be2 dopants in bulk silicon is measured for pressures up to 60 kbar and temperatures down to 9 K. PL from excitons bound to this Be2 trap is analyzed by using the Hopfield-Thomas-Lynch model, extended to treat more complex isoelectronic dopants, and several different binding potentials. This modified model describe...

In this article we review Raman studies of defects and dopants in graphene as well as the importance of both for device applications. First a brief overview of Raman spectroscopy of graphene is presented. In the following section we discuss the Raman characterization of three defect types: point defects, edges, and grain boundaries. The next section reviews the dependence of the Raman spectrum ...

The double gate MOSFET architecture has been proposed as a possible solution to allow the scaling of MOSFETs to the sub-30 nm regime, particularly due to its inherent resistance to short-channel effects. The use of lightly doped, or even undoped, channels means that such devices should be inherently resistant to random dopant induced fluctuations which will be one of the major obstacles to MOSF...