Cluster-doping in silicon nanocrystals.

Creating tin-alloyed silicon nanocrystals with tailored bandgap values is a significant challenge, primarily because a substantial concentration of tin is essential to observe useful changes in the electronic structure. However, high concentration of Sn leads to instability of the silicon-tin nanocrystals. This work introduces a completely new approach to doping and the modification of the electronic structure of nanoparticles by incorporating few-atom clusters in nanocrystals, deviating from isolated atom doping or attempting alloying.

Unexpected Electronic Features of NiO Quantum Dots Produced by Femtosecond Pulsed Laser Ablation in Water.

This study examines the effect of quantum confinement and surface orientations on the electronic properties of NiO quantum dots. It compares NiO nanocrystals produced via atmospheric-pressure microplasma and femtosecond laser (fs-laser) ablation in water, finding that both methods yield quantum-confined nanocrystals with a defined face-centered cubic lattice. Notably, fs-laser synthesis generates crystalline nanocrystals from both crystalline and amorphous targets.

Synthesis of water-stable and highly luminescent graphite quantum dots.

Highly stable and environmentally friendly nitrogen-doped graphite quantum dots consisting of ∼12 layers of graphene, average diameter of ∼7.3 nm, prepared by atmospheric pressure microplasma are reported to have blue emission due to surface states created by nitrogen doping (9 atomic%) and reaction with oxygen. The low-temperature synthesis method requires simple precursors in water, with no annealing or filtration, producing crystalline disc-shaped quantum dots with ∼68% photoluminescence emission quantum yield at 420 nm excitation and that have shown stability for more than one month after the synthesis.

Quasi-band structure of quantum-confined nanocrystals.

We discuss the electronic properties of quantum-confined nanocrystals. In particular, we show how, starting from the discrete molecular states of small nanocrystals, an approximate band structure (quasi-band structure) emerges with increasing particle size. Finite temperature is found to broaden the discrete states in energy space forming even for nanocrystals in the quantum-confinement regime quasi-continuous bands in k-space.

Multi-scale electronics transport properties in non-ideal CVD graphene sheet.

In this work, we benchmark non-idealities and variations in the two-dimensional graphene sheet. We have simulated more than two hundred graphene-based devices structure. We have simulated distorted graphene sheets and have included random, inhomogeneous, asymmetric out-of-plane surface corrugation and in-plane deformation corrugation in the sheet through autocorrelation function in the non-equilibrium Green's function (NEGF) framework to introduce random distortion in flat graphene.