We report on the influence of doping, temperature, porosity, band gap, and oxidation on the photoluminescence ~PL! properties of anodically etched porous a-Si:H and a-Si:C:H thin films. Only boron-doped, p-type a-Si:H samples exhibited visible photoluminescence. Two broad PL peaks at ;1.6 and ;2.2 eV are apparent in room temperature PL spectra. The intensity of the 2.2 eV peak as well as the na...

Impurity doping is the most important technique to functionalize semiconductor nanowires. The crucial point is how the states of impurity atoms can be detected. The chemical bonding states and electrical activity of boron (B) and phosphorus (P) atoms in germanium nanowires (GeNWs) are clarified by micro-Raman scattering measurements. The observation of B and P local vibrational peaks and the Fa...

The detailed knowledge of the distributions of carrier lifetimes, impurities and crystal defects in silicon ingots is key for understanding and improving wafer quality as well as solar cell processing steps. In this work, we have applied a quasi-steady-state photoconductance tester developed for the use on ingots to the measurement of lifetimes and dissolved iron concentrations along a p-type m...

Using density functional theory with local and non-local exchange and correlation (XC) functionals, as well as the Green’s function quasiparticle (GW) approach, we study the electronic structure of hexagonal boron nitride (h-BN) sheets, both pristine and doped with carbon. We show that the fundamental band gap in two-dimensional h-BN is different from the gap in the bulk material, and that in t...

Single molecule magnets and single spin centres can be individually addressed when coupled to contacts forming an electrical junction. To control and engineer the magnetism of quantum devices, it is necessary to quantify how the structural and chemical environment of the junction affects the spin centre. Metrics such as coordination number or symmetry provide a simple method to quantify the loc...

We have studied non-covalent functionalization of boron nitride nanotubes (BNNTs) with benzene molecule and with seven other different heterocyclic aromatic rings (furan, thiophene, pyrrole, pyridine, pyrazine, pyrimidine, and pyridazine, respectively). A hybrid density functional theory (DFT) method with the inclusion of dispersion correction is employed. The structural and electronic properti...

Single-layer graphene (SLG) supported on SiO(2) shows anomalously large chemical reactivity compared to thicker graphene, with charge inhomogeneity-induced potential fluctuations or topographic corrugations proposed as the cause. Here we systematically probe the oxidative reactivity of graphene supported on substrates with different surface roughnesses and charged impurity densities: hexagonal ...