Nanoscience and Nanotechnology Commons^™

Simulation Of Light Propagation Captured By Photoemission Electron Microscopy (Peem), Nabila Islam

Dissertations and Theses

The Photoemission electron microscopes (PEEM) is a powerful tool capable of synchronously imaging wave nature of light manifested by interference patterns as well as its particle nature through the energy exchange between the incident photons and the photoemitted imaging electrons. PEEM offers a non-invasive high-resolution approach for studying light propagation and interaction phenomena within a nanophotonic waveguide [7,8]. The electric field intensity variation of the interference pattern yielded by the interaction between the incident light and the guided mode coupled into the waveguide produces varying photoemission yields creating contrast in PEEM image. The guided modes cannot be excited simply by …

Fabrication And Characterization Of Photodetector Devices Based On Nanostructured Materials: Graphene And Colloidal Nanocrystals, Wafaa Gebril

Graduate Theses and Dissertations

Photodetectors are devices that capture light signals and convert them into electrical signals. High performance photodetectors are in demand in a variety of applications, such as optical communication, security, and environmental monitoring. Among many appealing nanomaterials for novel photodetection devices, graphene and semiconductor colloidal nanocrystals are promising candidates because of their desirable and unique properties compared to conventional materials.

Photodetector devices based on different types of nanostructured materials including graphene and colloidal nanocrystals were investigated. First, graphene layers were mechanically exfoliated and characterized for device fabrication. Self-powered few layers graphene phototransistors were studied. At zero drain voltage bias and room …

Statistical And Variational Modeling And Analysis Of Passive Integrated Photonic Devices, Norbert Dinyi Agbodo

Legacy Theses & Dissertations (2009 - 2024)

The success of Si as a platform for photonic devices and the associated availabilityof wafer-scale, ultra-high resolution lithography for Si CMOS has helped lead to the rapid advance of Si-based integrated photonics manufacturing over the past decade. This evolution is nearing the point of integration of Si-based photonics together with Si-CMOS for compact, high speed, high bandwidth, and cost-effective devices. However, due to the sensitive nature of passive and active photonic devices, variations inherent in wafer-based fabrication processes can lead to unacceptable levels of performance variation both within a give die and across a given wafer. Fully understanding the role …

Investigation Of Optical Second Harmonic Generation From Si (100) With Process Tailored Surface & Embedded Ag Nanostructures For Advanced Si Nonlinear Nanophotonics, Gourav Bhowmik

Legacy Theses & Dissertations (2009 - 2024)

The challenge of current microelectronic architecture in transmission bandwidth and power consumption can be potentially solved by using silicon photonics technologies that are compatible with modern CMOS fabrication. One of the critical active photonic devices for Si photonics is a Si based optical modulator. Most of the reported silicon modulators rely on the free carrier plasma dispersion effect. In those cases, a weak change of the refractive index obtained by carrier accumulation, injection or depletion is utilized in a Mach-Zehnder interferometer or a microring resonator to achieve intensity modulation, rendering them difficult for chip-level implementation due to a large footprint …

Photonic Grating Coupler Designs For Optical Benching, Eng Wen Ong

Legacy Theses & Dissertations (2009 - 2024)

Background: Silicon Photonics has been rapidly developing as a field. The primary reason for this is its lower operating costs and faster switching rates for use in big data centres. Instead of microns-wide copper lines to transmit signals, silicon photonic chips use waveguides, usually of silicon or silicon nitride. Photonic signals bypass the issues of resistive-capacitance lag (RC-lag) and resistive-heating encountered by copper lines. Additionally, a single waveguide may transmit multiple signals along different carrier wavelengths.

Tailoring The Optical Properties Of Silicon With Ion Beam Created Nanostructures For Advanced Photonics Applications, Perveen Akhter

Legacy Theses & Dissertations (2009 - 2024)

In today’s fast life, energy consumption has increased more than ever and with that the demand for a renewable and cleaner energy source as a substitute for the fossil fuels has also increased. Solar radiations are the ultimate source of energy but harvesting this energy in a cost effective way is a challenging task. Si is the dominating material for microelectronics and photovoltaics. But owing to its indirect band gap, Si is an inefficient light absorber, thus requiring a thickness of solar cells beyond tens of microns which increases the cost of solar energy. Therefore, techniques to increase light absorption …

White-Light And Infrared Emission From Sicxoy-Based Materials, Vasileios Nikas

Legacy Theses & Dissertations (2009 - 2024)

The development of a Si-based light source has attracted a high level of attention due to its potential unique advantages. For one, the monolithic integration of photonics on on-chip level along with the microelectronics devices would enhance the data processing rate. Additionally the cost per transmitted/processed information capacity can be significantly reduced.