Nano

In this paper, we discuss and compare various nanocage materials proposed theoretically as storage medium for hydrogen. Doping of transition elements leads to clustering which reduces the gravimetric density of hydrogen, while doping of alkali and alkali-earth metals on the nanocage materials, such as carborides, boronitride, and boron cages, were stabilized by the charger transfer from the dopant to the nanocage. Further, the alkali or alkali-earth elements exist with a charge, which are found to be responsible for the higher uptake of hydrogen, through a dipole–dipole and change-induced dipole interaction. The binding energies of hydrogen on these systems were found to be in the range of 0.1 eV to 0.2 eV, which are ideal for the practical applications in a reversible system.

This paper reviews research works carried out on silicon quantum dots (Si-QDs) embedded in the silicon nitride (SiN_x) dielectric matrix films with different fabrication techniques and different characteristics. The advantages of SiN_x as a dielectric compared to silicon dioxide (SiO₂) for Si-QDs from a device point of view are discussed. Various fabrication techniques along with different optimized deposition conditions are summarized. The typical results of structural characteristics of the films with Raman spectroscopy and Transmission Electron Microscopy (TEM) are discussed. The origin of photoluminescence (PL) from the films and the chemical compositional analysis such as X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Secondary Ion Mass Spectroscopy (SIMS) analysis of the films are also made available in brief. The charge conduction mechanism in the films with metal–insulator–semiconductor (MIS) structure, with their electrical characterization like capacitance–voltage (C–V) and current–voltage (I–V) measurements are presented.

Polymerization of C₆₀, Ce₂@C₈₀, and Lu₂@C₇₆ metallofullerenes induced by electron injection from a scanning tunneling microscope (STM) tip has been studied. C₆₀ polymerization has been observed only with C₆₀ multilayer on Au(111) and not with C₆₀ monolayer on Au(111). The Ce_2@C80 metallofullerene on Si(111)-7 × 7 also polymerizes by electron injection but has less polymerization reactivity than C₆₀. Interestingly, the Lu₂@C₇₆ metallofullerene on Si(111)-7 × 7 does not show any polymerization. Based on these STM observations on the tip-induced polymerization, the direction of the bond formation and the dependence of reactivity on the kind of fullerenes are discussed.

The basic technique of stimulated Raman adiabatic passage for laser-induced adiabatic population transfer between discrete quantum states of an asymmetric double quantum well has been used in our study. The results show that the proper time-delay, overlap, and detuning of two pulses allows the coherent transfer between the states of a double quantum well system, leading to the possibility of implementation of semiconductor–based quantum logic gates and high efficiency optical switches. The impact of phase relaxation on the population transfer efficiency is also studied.

Several ionic fullerene salts have been prepared based on a fulleropyrrolidine pyridinium cation and four different anions. The initial ionic fullerene can be easily prepared by quaternization of a pyridine-appended fulleropyrrolidine derivative in high yield. Anion exchange is a simple procedure giving several different salts of varying polarity. In addition to their characterization, the quantitative solubility of these salts has been studied in seven different solvents, including an imidazolium ionic liquid.

It has been recently shown that inhomogeneity of a multilayer structure and optimization of annealing time give us the possibility to decrease the depth of p–n-junctions, which were produced in the structures. The additional to the considered effect is increasing of homogeneity of dopant distribution in enriched by the dopant area of p–n-junction. In the present paper analysis of dopant redistribution in a multilayer structures during production a series of p–n-junctions, which was produced in the multilayer structures, has been done. We consider an approach to increase the sharpness of both diffused-junction and implanted-junction rectifiers, which comprise in a bipolar transistor or thyristor, and increasing of homogeneity of dopants distributions in enriched by the dopants areas of p–n-junctions. The approach gives us possibility to increase the degree of integration of p–n-junctions, which was produced as elements of integrated circuits. Optimization of annealing time for simultaneously increasing of the sharpness and homogeneity has been done.