Cathodoluminescence is used to measure the recombination velocity of heterointerfaces between Cu2ZnSnS4 (CZTS) and CuxSnySz, SnS secondary phases precipitated along grain boundaries as well ZnS within CZTS interiors. The CZTS/CuxSnySz CZTS/ZnS had velocities smaller than bulk carrier diffusion while opposite true for CZTS/SnS heterointerface. Secondary having crystal structures compatible with (e.g., ZnS, Cu2SnS3) are likely form small misfit strain hence low interfacial velocity....

Abstract 5% (molar ratio) Fe doped TiO 2 nanoparticles were prepared by a sol gel method and the post annealing of samples was carried out at 400 °C, 600 °C 800 °C in air. Structural characterization using High Resolution Transmission Electron Microscopy (HRTEM). HRTEM images revealed that mean size changed from ∼8 nm to ∼100 nm as temperature increased. Experimental investigation electronic structure :Fe is important order understand correlation between optical properties these samples....

ABSTRACT Chemical analysis of individual atom columns was carried out to determine the crystal structure and local point defect chemistry Cu 2 ZnSnS 4 . Direct evidence for a nanoscale composition inhomogeneity, in form Zn enrichment depletion, obtained. The lateral size inhomogeneity estimated be between ~1.5 5 nm. Photoluminescence confirmed presence broad donor–acceptor transition consistent with observed cation disorder. Areas relatively high concentration + antisite donors locally...

The crystal structure of Sb2Se3 gives rise to unique properties that cannot otherwise be achieved with conventional thin-film photovoltaic materials, such as CdTe or Cu(In,Ga)Se2. It has previously been proposed grain boundaries can made benign provided only the weak van der Waals forces between (Sb4Se6)n ribbons are disrupted. Here, it is shown non-radiative recombination suppressed even for cutting across ribbons. This due a remarkable self-healing process, whereby atoms at boundary relax...

Bloch waves are often used in dynamical diffraction calculations, such as simulating electron intensities for crystal structure refinement. However, this approach relies on matrix diagonalization and is therefore computationally expensive large unit cell crystals. Here wave theory re-formulated using the physical optics concepts underpinning multislice method. In particular, phase grating propagator functions expressed form elements of matrix. The specimen divided into thin slices, evolution...

Graphene has generated much interest owing to its exceptional electronic properties and high mechanical strength. This enabled new types of devices composite materials be envisaged. The main problem is the availability material difficulties associated with synthesis. Here we have used a simple, convenient scalable chemical vapour deposition method involving sodium ethoxide in ethanol produce few-layer graphene sheets or platelets. process advantage that it can grow films on non-metal...

We show that small (≤4%) amounts of water which detonation-produced nano-diamond powder always adsorbs spontaneously from air can increase its dielectric permittivity (ε) at low frequencies single digits to over 1019, by far the highest value observed for any system including ferroelectrics. Conversely, traces DND drastically affect physical properties water, increasing ε ∼80 106 and altering sound velocity. The effect is due proton-releasing functional groups on diamond surface interacting...

A cathodoluminescence-based, contactless method for extracting the bulk minority carrier diffusion length and reduced recombination velocity of an individual grain boundary is applied to vapor grown CdTe epitaxial films. The measured was within range 0.4–0.6 μm varied from 500 750 cm/s. technique can be used investigate effect boundaries on photovoltaic performance.

The growth of Cu2ZnSnS4 (CZTS) polycrystals from solid state reaction over a range compositions, including the regions which produce highest efficiency photovoltaic devices, is reported. X-ray measurements confirm crystalline CZTS. Temperature and intensity dependent photoluminescence (PL) show an increase in energy main CZTS luminescence peak with both increasing laser power temperature. Analysis PL positions behavior demonstrates that results are consistent model fluctuating potentials....

Electron-energy-loss spectroscopy is used to map composition and electronic states in epitaxial La2/3Ca1/3MnO3 (LCMO) films of various thicknesses grown on SrTiO3 (001) (110) substrates. For relatively thick (≥20 nm), tensile strain promotes a compositional La/Ca gradient across the film thickness, being interface La rich, while relaxed are chemically homogeneous. In contrast, much thinner LCMO display different distribution, rich at free surface. The observed distinct thickness-dependent...

Thermodynamic control of crystallization has been achieved to produce stable polymorphs directly by using three-dimensional (3D) nanoconfinement in microemulsions. The theoretical basis for thermodynamic 3D is outlined. Our approach leap-frogs the usual metastable polymorph pathway because becomes governed ability form nuclei, rather than critical nuclei. generality this demonstrated crystallizing three "problem" compounds from microemulsions under conditions yielding forms bulk solution....

A method for fabricating single crystal silicon nanowires is presented using top-down optical lithography and anisotropic etching. Wire diameters as small 10 nm are demonstrated on insulator substrates. Structural characterization confirms that wires straight, have a triangular cross section without breakages over lengths of tens microns. Electrical indicates bulk like mobility values, not strongly influenced by surface scattering or quantum confinement. Processing compatible with...

The use of CdSe layers has recently emerged as a route to improving CdTe photovoltaics through the formation CdTe(1-x)Sex (CST) phase. However, extent Se diffusion and influence it on grain structure not been widely investigated. In this study, we used transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), backscatter diffraction (EBSD) investigate impact growing three different window layer structures CdS, CdSe, CdS/CdSe. We demonstrate that extensive...

Abstract The Nye tensor characterizes the strength of infinitesimal dislocations at each point in a continuously dislocated crystal, and provides measure Burgers vector extent dislocation dissociation. present work employs this description to analyze ½ screw bcc Mo obtained by Finnis–Sinclair, Bond Order Potential first-principles simulations an attempt detect misfit core region. spatial distribution fractional are calculated compared between different simulated structures. technique is also...

Radial p-n junction nanowire (NW) solar cells with high densities of CdTe NWs coated indium tin oxide (ITO)/ZnO/CdS triple shells were grown excellent heterointerfaces. The optical reflectance the devices was lower than for equivalent planar films by a factor 100. best efficiency NW η = 2.49%, current transport being dominated recombination, and conversion efficiencies limited back contact barrier (ϕB 0.52 eV) low shunt resistances (RSH < 500 Ω·cm2).