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

Engineering Science and Materials Commons

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

Articles 1 - 4 of 4

Full-Text Articles in Engineering Science and Materials

Ii-Vi Semiconductor Nano-Structures For On-Chip Integrated Photonics, Jacob Stern Berger Jan 2016

Ii-Vi Semiconductor Nano-Structures For On-Chip Integrated Photonics, Jacob Stern Berger

Publicly Accessible Penn Dissertations

Nanowires (NWs) and nanobelts (NBs) have been widely studied and fabricated into on-chip photodetectors, biosensors, LEDs/lasers, solar cells and computational components. Their highly tunable physical, electronic and optical properties have generated interest in this field over the past two decades. While there is tremendous potential for nano-structured devices, the wide spread application of NWs/NBs has been hindered by the difficulty in integrating multiple NW or NB structures together into more complex devices. This problem requires a completely novel approach to what has been previously attempted in order to effectively couple on-chip light sources, waveguides and detectors. Multiple factors ...


Deformation Mechanisms In Pd Nanowhiskers, Lisa Yingying Chen Jan 2014

Deformation Mechanisms In Pd Nanowhiskers, Lisa Yingying Chen

Publicly Accessible Penn Dissertations

The reduced length scales inherent in nanoscale materials enable access to properties that are otherwise not achievable in bulk. The application of their novel structural and functional responses however is hindered by a lack of understanding of their mechanical behavior, which affects their assimilation into device fabrication as well as their reliability during performance. In contrast to bulk materials, nanoscale materials possess a non-negligible proportion of surface atoms, which can exert significant influence on the overall mechanical response. In addition, structures with small volumes can possess much lower defect densities, which could potentially be driven out of the volume instead ...


Electrical Percolation In Metal Nanowire Networks For Bulk Polymer Nanocomposites And Transparent Conductors, And Resistive Switching In Metal/Polymer Nano-Gap Devices, Rose Mumbe Mutiso Jan 2013

Electrical Percolation In Metal Nanowire Networks For Bulk Polymer Nanocomposites And Transparent Conductors, And Resistive Switching In Metal/Polymer Nano-Gap Devices, Rose Mumbe Mutiso

Publicly Accessible Penn Dissertations

This dissertation describes the electrical properties of metal nanowire-polymer hybrid systems. The first part of the thesis discusses electrical percolation of metal nanowire networks in bulk polymer nanocomposites (3D) and nanowire films (quasi-2D). Specifically, we integrate simulations of rod networks and experiments of model metal nanowire systems to establish the dependence of their electrical properties on the nanowire aspect ratio (L/D) and network structure. For bulk polymer nanocomposites, we find that narrow Gaussian distributions in filler size do not impact the electrical percolation threshold, while mixing small fractions of high-L/D rods with modest-L/D rods significantly reduces the ...


Semiconductor Nanowires: Optical Properties And All-Optical Switching, Brian Edward Piccione Jan 2012

Semiconductor Nanowires: Optical Properties And All-Optical Switching, Brian Edward Piccione

Publicly Accessible Penn Dissertations

The optical properties of semiconductor nanowires are both important from a fundamental materials physics standpoint and necessary to understand in engineering applications: nanowire photovoltaic devices, sensors, and lasers, among others, could all benefit. Unfortunately, these optical properties are not easy to ascertain. Transmission times are short, in-coupling of white probe light is difficult, and the angle-resolved measurements typically used to determine material dispersion relations in bulk materials are hindered by diffraction effects at subwavelength nanowire end facets.

Here, we present a series of experimental techniques and theoretical models developed to study of the optical properties of active nanowire waveguides. Beginning ...