We have applied scanning tunneling spectroscopy in studies of the electronic level structure of surface-functionalized colloidal Si nanocrystals (Si-NCs) as a function of their size for various capping ligands. The energy gaps extracted from the tunneling spectra increase with decreasing NC size, manifesting the effect of quantum confinement. This is consistent with the blueshift revealed by photoluminescence (PL) from dodecene functionalized Si-NCs. The tunneling spectra measured on NCs functionalized with NH4Br or allylamine show band-edge shifts toward higher energies, akin to p-type doping. This behavior can be accounted for by the combined contributions of the ligands’ dipole moments and charge transfer between a Si-NC and its surface groups. Concomitantly, size-independent PL spectra, which cannot be associated with NC band gap variations, were observed for the latter Si-NCs.

Doping and quantum confinement effects in single Si nanocrystals observed by scanning tunneling spectroscopy.

A microchannel plate for detecting neutrons includes a hydrogen-rich polymer substrate that defines a plurality of channels extending from a top surface of the substrate to a bottom surface of the substrate, where neutrons interact with the plurality of channels to generate at least one secondary electron. A top electrode is positioned on the top surface of the substrate and a bottom electrode is positioned on the bottom surface of the substrate. A resistive layer is formed over an outer surface of the plurality of channels that provides ohmic conduction with a resistivity that is substantially constant. An emissive layer is formed over the resistive layer. Neutron interaction products interact with the plurality of channels defined by the substrate and the emissive films to generate secondary electrons that cascade within the plurality of channels to provide an amplified signal related to the detection of neutrons.

Microchannel plate devices with tunable resistive films

Boron diffusion into nitrogen doped silicon films for P+ polysilicon gate structures

The photoluminescence (PL) from silicon nanocrystals (Si-ncs) embedded in an amorphous silicon nitride matrix was examined both experimentally and through theoretical simulations. The film was prepared using low-pressure chemical vapor deposition with subsequent high-temperature annealing. The experimental parameters required for the PL modeling were determined using Raman spectroscopy. A novel method to estimate the nitrogen content, which allowed the determination of both the Urbach energy and the Tauc gap, was reported. The luminescence could be attributed to different origins, namely, Si-ncs, amorphous silicon nanodots, nitrogen and silicon defects, and amorphous matrix. A comparison between the experimental results and the modeling indicated that the existing models are unable to satisfactorily explain the observed PL.

Photoluminescence from silicon nanocrystals embedded in silicon nitride fabricated by low-pressure chemical vapor deposition followed by high-temperature annealing

A memory element (3) arranged in matrix in a memory device and including a resistance variable element (1) which switches its electrical resistance value in response to a positive or negative electrical pulse applied thereto and retains the switched electrical resistance value; and a current control element (2) for controlling a current flowing when the electrical pulse is applied to the resistance variable element (1); wherein the current control element (2) includes a first electrode; a second electrode; and a current control layer sandwiched between the first electrode and the second electrode; and wherein the current control layer comprises SiNx, and at least one of the first electrode and the second electrode comprises α-tungsten

E Couderc

Papers

Properties of nitrogen doped silicon films deposited by low pressure chemical vapour deposition from disilane and ammonia