Open Access. Powered by Scholars. Published by Universities.®

Physics Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 3 of 3

Full-Text Articles in Physics

Tensile Gaas(111) Quantum Dashes With Tunable Luminescence Below The Bulk Bandgap, Paul J. Simmonds Aug 2014

Tensile Gaas(111) Quantum Dashes With Tunable Luminescence Below The Bulk Bandgap, Paul J. Simmonds

Paul J. Simmonds

Strain-based band engineering in quantum dots and dashes has been predominantly limited to compressively strained systems. However, tensile strain strongly reduces the bandgaps of nanostructures, enabling nanostructures to emit light at lower energies than they could under compressive strain. We demonstrate the self-assembled growth of dislocation-free GaAs quantum dashes on an InP(111)B substrate, using a 3.8% tensile lattice-mismatch. Due to the high tensile strain, the GaAs quantum dashes luminesce at 110–240 meV below the bandgap of bulk GaAs. The emission energy is readily tuned by adjusting the size of the quantum dashes via deposition thickness. Tensile self-assembly creates new opportunities …


Deposition And Characterization Of Pbo--Pbs Multilayer Thin Films By Solution Growth Technique, Dominic Eya Jan 2014

Deposition And Characterization Of Pbo--Pbs Multilayer Thin Films By Solution Growth Technique, Dominic Eya

Turkish Journal of Physics

PbO-PbS thin films were deposited on glass substrates using the chemical bath deposition (CBD) technique. PbO thin films were deposited from the solution of lead nitrate (Pb(NO_3)_2) and sodium hydroxide (NaOH). Ethylenediaminetetraacetate (EDTA) served as the complexing agent. Some of the PbO films were used as substrate for the deposition of PbS. The PbS was deposited from alkaline solution of lead nitrate and thioacetamide. Triethanolamine was used as the complexing agent. Some of the films were subjected to thermal treatment after deposition. Energy dispersive X-ray fluorescence analysis confirmed the presence of Pb and S in the PbS thin films, while …


Digitally Manufactured Spatially Variant Photonic Crystals, Javier Jair Pazos Jan 2014

Digitally Manufactured Spatially Variant Photonic Crystals, Javier Jair Pazos

Open Access Theses & Dissertations

Metamaterials and photonic crystals are engineered composites that exhibit electromagnetic properties superior to those found in nature. They have been shown to produce novel and useful phenomena that allow extraordinary control over the electromagnetic field. One of these phenomena is self-collimation, an effect observed in photonic crystals in which a beam of light propagates without diffraction and is forced to flow in the direction of the crystal. Self-collimation however, like many of the mechanisms enabled through dispersion engineering, is effective in directions only along the principal axes of the lattice. To this effect, a general purpose synThesis procedure was developed …