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

Nanoscience and Nanotechnology Commons

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

Articles 1 - 4 of 4

Full-Text Articles in Nanoscience and Nanotechnology

Graphene-Semiconductor Heterojunctions And Devices, Tzu-Min Ou Apr 2015

Graphene-Semiconductor Heterojunctions And Devices, Tzu-Min Ou

Electrical, Computer & Energy Engineering Graduate Theses & Dissertations

In this thesis we explore the potential of versatile graphene-semiconductor heterojunctions in photodetection and field-effect transistor (FET) applications. The first part of the thesis studies near-infrared photodiode (NIR PD) based on a graphene- n-Si heterojunction in which graphene is used as the absorbing medium. Graphene is chosen for its absorption in NIR wavelengths to which Si is not responsive. Most graphene detectors in the literature are photoconductors that have a high dark current. The graphene-Si heterojunction PD has a large Schottky barrier height that suppresses the dark current and enhances the current rectification and the photon detectivity.

The fabricated graphene-Si ...


Plasmonic Nanostructures For The Absorption Enhancement Of Silicon Solar Cells, Nathan Matthias Burford May 2013

Plasmonic Nanostructures For The Absorption Enhancement Of Silicon Solar Cells, Nathan Matthias Burford

Theses and Dissertations

In this work, computational investigation of plasmonic nanostructures was conducted using the commercial finite element electromagnetics solver Ansys® HFSS. Arrays of silver toroid nanoparticles located on the surface of an amorphous silicon thin-film absorbing layer were studied for particle sizes ranging from 20 nm to 200 nm in outer diameter. Parametric optimization by calculating an approximation of the photocurrent enhancement due to the nanoparticles was performed to determine optimal surface coverage of the nanoparticles. A comparison was made between these optimized nanotoroid arrays and optimized nanosphere arrays based on spectral absorption enhancement and potential photocurrent enhancement in an amorphous silicon ...


Synthesis And Characterization Of Iron Pyrite Nanocrystals For Photovoltaic Devices, Scott Curtis Mangham May 2013

Synthesis And Characterization Of Iron Pyrite Nanocrystals For Photovoltaic Devices, Scott Curtis Mangham

Theses and Dissertations

Iron pyrite nanocrystals have been synthesized using a hot-injection method with a variety of amines and characterized with properties necessary for photovoltaic devices. The iron pyrite nanocrystals were characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, optical absorption, micro-Raman, and micro-Photoluminescence. The optical absorbance spectra showed the large absorption in the visible and near infrared spectral range for the nanocrystals as well as to show the band gap. The face-centered cubic crystal structure of the iron pyrite nanocrystals was shown by matching the measured X-ray diffraction pattern to a face-centered cubic iron pyrite reference pattern. Using Bragg's ...


Nanoprobe I-V Characterization Of Cdte/Cds Micro And Nano-Patterned Solar Cells, Heber Prieto Jan 2012

Nanoprobe I-V Characterization Of Cdte/Cds Micro And Nano-Patterned Solar Cells, Heber Prieto

Open Access Theses & Dissertations

This thesis presents a novel way to characterize micro and nano patterned cadmium telluride thin film solar cells via a nano-probe system. A historical review of CdTe-based solar cells is presented first followed by review of the technology developed to produce the patterned CdTe cells. A detailed presentation is then provided on the use of a Zyvex nanoprobing system to characterize the patterned solar cells. The I-V response of micro- and nano-patterned solar cells stimulated under different e-beam conditions is presented and analyzed. Suggestions of how to improve the technique are provided. This work documents, for the first time, the ...