Physical Sciences and Mathematics Commons^™

Si Nanocrystal Synthesis Via Double Implantation And Variable Implantation, James M. Gaudet

Electronic Thesis and Dissertation Repository

Silicon (Si) nanocrystals (nc) precipitated from silicon-implanted silicon oxide (SiO₂) are of interest as a novel light source for illumination, biomedical applications, optical computing, etc. They have some advantages over conventional III-V compound semiconductor nanocrystals produced by colloidal synthesis. They are compatible with Si/SiO₂ based semiconductor processing, are stable, non-toxic at point of synthesis and consumption, and their luminescence falls with the infrared transmission window of biological materials. Unfortunately, synthesis of Si-nc embedded SiO₂ is uneconomical and is not as amenable to precise control of the size distribution of nanocrystals as is the case for III-V …

Synthesis And Characterization Of Ion-Implanted Gold Nanoparticles, Nurlathifah Fnu

Masters Theses

Gold negative ions of 70 keV energy were implanted within the quartz substrates at room temperature at seven different fluences starting from 2 x 10¹⁶ particles/cm² to 8 x 10¹⁶ particles/cm² with the increment of 1 x 10¹⁶. Prior to the implantation, Stopping and Range of Ions in Matter (SRIM) calculations were carried to obtain the Bragg peak below the surface of quartz. Rutherford Backscattering Spectrometry (RBS) was carried out using 2.0 MeV He⁺⁺ ions to measure depth and implanted fluence of gold, and learn how they varied with fluence. Backscattered He particles …

Embedded Silver Nanoparticles For Metal Enhanced Photoluminescence, Shahid Iqbal

Dissertations

Imaging of biologically significant molecules using plasmons of Metal Nanoparticles (MNPs) is gaining attention in the research community. Localized Surface Plasmon Resonance (LSPR) is the coherent oscillation of conduction electrons of MNPs. The biologically significant molecule is labeled with the fluorophore molecule to get the image. This approach is widely used in clinical practices, however, low intensity light emission from the labeled molecule makes it difficult to image the biologically significant material. One way to improve the weak intensities of fluorophore is to enhance the brightness using a process called Metal Enhanced Photoluminescence (MEP). This phenomenon occurs in the close …

Laser-Spark Multicharged Ion Implantation System ‒ Application In Ion Implantation And Neural Deposition Of Carbon In Nickel (111), Oguzhan Balki

Electrical & Computer Engineering Theses & Dissertations

Carbon ions generated by ablation of a carbon target using an Nd:YAG laser pulse (wavelength λ = 1064 nm, pulse width τ = 7 ns, and laser fluence of 10-110 J/cm²) are characterized. Time-of-flight analyzer, a three-mesh retarding field analyzer, and an electrostatic ion energy analyzer are used to study the charge and energy of carbon ions generated by laser ablation. The dependencies of the ion signal on the laser fluence, laser focal point position relative to target surface, and the acceleration voltage are described. Up to C⁴⁺ are observed. When no acceleration voltage is applied between …

Properties Of Si Quantum Dots, Carolyn C. F Cadogan

Electronic Thesis and Dissertation Repository

The fundamental properties of matter in confined particles change dramatically due to quantum effects. In this work, we have explored the optical properties of silicon quantum dots (Si-QDs) embedded in Si₃N₄; and the role of crystallinity on the optical properties and formation of Si-QDs in Al₂O₃. This work examined the role of (1) annealing temperature and the composition of the film, (2) Al doping of the host Si₃N₄ film, (3) doping Si-QDs and (4) Al and P passivation of Si-QDs on the PL intensity of Si-QDs embedded in Si …

Development Of A Laser-Spark Multicharged Ion System – Application In Shallow Implantation Of Sic By Boron And Barium, Md. Haider Ali Shaim

Electrical & Computer Engineering Theses & Dissertations

A novel multicharged ion source, using laser ablation induced plasma coupled with spark discharge, has been investigated in this work. The designed and demonstrated ion source is cost-effective, compact and versatile. Experiments are described with the intention of demonstrating the practicability of ion implantation via laser ion source.

Multicharged aluminum ions are generated by a ns Q-switched Nd:YAG laser pulse ablation of an aluminum target in an ultrahigh vacuum. The experiments are conducted using laser pulse energies of 45–90 mJ focused on the Al target surface by a lens with an 80-cm focal length to 0.0024 cm² spot area …

Exploring Magnetic Nanostructures Embedded Within Single-Crystal Silicon For Generation Of Spin-Polarized Carriers, Machara Krishna Girish Malladi

Legacy Theses & Dissertations (2009 - 2024)

Integrating magnetic functionalities with silicon holds the promise of developing, in the most dominant semiconductor, a paradigm-shift information technology based on the manipulation and control of electron spin and charge. Here, we demonstrate an ion implantation approach enabling the synthesis of a ferromagnetic layer within a defect free Si environment by exploiting an additional implant of hydrogen in a region deep below the metal implanted layer. Upon post-implantation annealing, nanocavities created within the H-implanted region act as trapping sites for gettering the implanted metal species, resulting in the formation of metal nanoparticles in a Si region of excellent crystal quality. …

Ion Implantation In Zno : Defect Interaction And Impurity Diffusion, Faisal Yaqoob

Legacy Theses & Dissertations (2009 - 2024)

In the first part of this research we studied the entropy changes in diffusion prefactor and its

Localized Surface Plasmon Resonance Induced Structure-Property Relationships Of Metal Nanostructures, Subramanian Vilayurganapathy

Dissertations

The confluence of nanotechnology and plasmonics has led to new and interesting phenomena. The industrial need for fast, efficient and miniature devices which constantly push the boundaries on device performance tap into the happy marriage between these diverse fields. Designing devices for real life application that give superior performance when compared with existing ones are enabled by a better understanding of their structure-property relationships. Among all the design constraints, without doubt, the shape and size of the nanostructure along with the dielectric medium surrounding it has the maximum influence on the response and thereby the performance of the device. Hence …

Experimental And Theoretical Analysis Of Strain Engineered Aluminium Nitride On Silicon For High Quality Aluminium(X)Indium(Y)Gallium(1-X-Y)Nitride Epitaxy, Mihir Hemant Tungare

Legacy Theses & Dissertations (2009 - 2024)

III-Nitrides on Si are of great technological importance due to the availability of large area, epi ready Si substrates and the ability to heterointegrate with mature silicon micro and nanoelectronics. The major roadblock with realizing this is the large difference in thermal expansion coefficients and lattice constants between the two material systems. A novel technique developed in our research lab shows the potential of simultaneous and substantial reduction in dislocation and crack density in GaN on Si (111). Research undertaken in the current doctoral dissertation, validates the superior GaN quality on Si obtained using our technique and determines the factors …

In-Implanted Zno: Controlled Degenerate Surface Layer, David C. Look, Gary C. Farlow, F. Yaqoob, L. H. Vanamurthy, M. Huang

Physics Faculty Publications

In was implanted into bulk ZnO creating a square profile with a thickness of about 100 nm and an In concentration of about 1×10²⁰ cm^-3. The layer was analyzed with Rutherford backscattering, temperature-dependent Hall effect, and low-temperature photoluminescence measurements. The implantation created a nearly degenerate carrier concentration n of about 2×10¹⁹ cm^-3, but with a very low mobility μ, increasing from about 0.06 cm²/V s at 20 K to about 2 cm²/V s at 300 K. However, after annealing at 600 °C for 30 min, n increased to about 5×10 …

Electrical Activation Studies Of Silicon Implanted AlXGa1-XN, Timothy W. Zens

Theses and Dissertations

Electrical activation studies of silicon implanted Al_xGa_1-xN grown on sapphire substrates were conducted as a function of ion dose, anneal temperature, and anneal time. Silicon ion doses of 1x10¹³, 5x10¹³, and 1x10¹⁴ cm^-2 were implanted in AlxGa1-xN samples with aluminum mole fractions of 0.1 and 0.2 at an energy of 200 keV at room temperature. The samples were proximity cap annealed at temperatures from 1100 to 1350 ºC and anneal times of 20 to 40 minutes with a 500 Å thick AlN cap in a nitrogen environment. The Hall coefficient …

Electrical Characterization Of Ion-Implanted 4h-Silicon Carbide, Christian P. Morath

Theses and Dissertations

Electrical characterization has been performed on ion-implanted p-type 4H-SiC to assess the activation efficiency and implantation-related damage recrystallization with the intention of developing an implantation/annealing scheme. Low doped (Na - Nd = 5x10(exp 15)/cu cm) epitaxial p-type layers grown by MOCVD were implanted with Al or B at doses ranging from 1x10(exp 13) to 1x10(exp 14)/sq cm at room temperature or 500 deg. C. The electrical technique of Temperature Dependent Hall Effect (TDHE) indicated that Al and B act as shallow acceptors 4H-SiC with ionization energies of ^252 and ^285 meV, respectively. The highest activation efficiency for Al and B …

Luminescence Study Of Ion-Implanted Gallium Nitride, Eric Silkowski

Theses and Dissertations

Luminescence and absorption measurements were used to demonstrate the efficacy of ion implantation for introducing various classes of dopants into GaN. A wide range of implantation and annealing studies were performed with several dopant species (Ar, Zn, C, O, Si, Be, Mg, Nd, Er). Room temperature ion implantation was performed on MOCVD- and MBE-grown GaN samples at energies between 100 and 1150 keV with doses ranging from 1 x 10¹³ to 1 x 10¹⁵/cm^-2. Conventional furnace annealing in flowing NH₃ or N₂ gas resulted in good implantation damage recovery at an annealing temperature …

Ion Beam Mixing In Ag-Pd Alloys, J L. Klatt, R S. Averback, David Peak

All Physics Faculty Publications

Ion beam mixing during 750 keV Kr⁺ irradiation at 80 K was measured on a series of Ag‐Pd alloys using Au marker atoms. The mixing in pure Ag was the greatest and it decreased monotonically with increasing Pd content, being a factor of 10 higher in pure Ag than in pure Pd. This large difference in mixing cannot be explained by the difference in cohesion energy between Ag and Pd in the thermodynamic model of ion beam mixing proposed by Johnson et al. [W. L. Johnson, Y. T. Cheng, M. Van Rossum, and M‐A. Nicolet, Nucl. …

Electrical Characterization Of Ion Implantation Into Gaas, David C. Look

Physics Faculty Publications

Recent advances in the characterization of ion‐implanted samples have included whole wafer mapping (topography) and depth profiling techniques. We review several methods for mapping electrical parameters, including the dark‐spot resistance (DSR), and the microwave photoconductance techniques. In addition, we suggest a new photo‐Hall technique which would allow mobility and carrier‐concentration mapping as well as that of resistivity . Finally, we review methods for obtaining ρ, μ, and depth profiles, with particular emphasis on the application of the magnetoresistance techniques in actual field‐effect transistor structures.

Ohmic Contacts To Al‐Implanted Znse, B. K. Shin, David C. Look, Y. S. Park

Physics Faculty Publications

No abstract provided.