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Signal Modulation in a High Voltage Plasma

Description

A high voltage plasma arc can be created and sustained in air by subjecting the gases to an electric field with high voltage potential, causing ionization. The internal energy of the ionized gases can be transferred to corresponding pressure waves

A high voltage plasma arc can be created and sustained in air by subjecting the gases to an electric field with high voltage potential, causing ionization. The internal energy of the ionized gases can be transferred to corresponding pressure waves when the matter involved switches between the gaseous and plasma states. By pulse-width modulating a transformer driving signal, the transfer of internal electrical energy to resonating pressure waves may be controlled. Audio wave input to the driver signal can then be modulated into the carrier wave and be used to determine the width of each pulse in the plasma, thus reconstructing the audio signal as pressure, or sound waves, as the plasma arc switches on and off. The result will be the audio waveform resonating out of the plasma arc as audible sound, and thus creating a plasma loudspeaker. Theory of operation was tested through construction of a plasma arc speaker, and resultant audio playback was analyzed. This analysis confirmed accurate reproduction of audio signal in audible sound.

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2014-05

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An Economic Perspective -- Hybrid Solar Modules: Harnessing Solar Energy for Electrical and Thermal Applications

Description

A hybrid PV/T module was built, consisting of a thermal liquid heating system and a photovoltaic module system that combine in a hybrid format. This report will discuss the work on the project from Fall 2012 to Spring 2013 and

A hybrid PV/T module was built, consisting of a thermal liquid heating system and a photovoltaic module system that combine in a hybrid format. This report will discuss the work on the project from Fall 2012 to Spring 2013 and the extended section on the economics for the Honors Thesis. Three stages of experiments were completed. Stage 1 showed our project was functional as we were able to verify our panel produced electricity and increased the temperature of water flowing in the system by 0.65°C. Stage 2 testing included “gluing” the flow system to the back of the panel resulting in an average increase of 4.76°C in the temperature of the water in the system. Stage 3 testing included adding insulating foam to the module which resulted in increasing the average temperature of the water in our flow system by 6.95°C. The economic calculations show the expected energy cost savings for Arizona residents.

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2013-05

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ZnTe nanostructural synthesis for electronic and optoelectronic devices

Description

Zinc telluride (ZnTe) is an attractive II-VI compound semiconductor with a direct

bandgap of 2.26 eV that is used in many applications in optoelectronic devices. Compared

to the two dimensional (2D) thin-film semiconductors, one-dimensional (1D)

nanowires can have different electronic properties for potential

Zinc telluride (ZnTe) is an attractive II-VI compound semiconductor with a direct

bandgap of 2.26 eV that is used in many applications in optoelectronic devices. Compared

to the two dimensional (2D) thin-film semiconductors, one-dimensional (1D)

nanowires can have different electronic properties for potential novel applications.

In this work, we present the study of ZnTe nanowires (NWs) that are synthesized

through a simple vapor-liquid-solid (VLS) method. By controlling the presence or

the absence of Au catalysts and controlling the growth parameters such as growth

temperature, various growth morphologies of ZnTe, such as thin films and nanowires

can be obtained. The characterization of the ZnTe nanostructures and films was

performed using scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy

(EDX), high- resolution transmission electron microscope (HRTEM), X-ray

diffraction (XRD), photoluminescence (PL), Raman spectroscopy and light scattering

measurement. After confirming the crystal purity of ZnTe, two-terminal diodes and

three-terminal transistors were fabricated with both nanowire and planar nano-sheet

configurations, in order to correlate the nanostructure geometry to device performance

including field effect mobility, Schottky barrier characteristics, and turn-on

characteristics. Additionally, optoelectronic properties such as photoconductive gain

and responsivity were compared against morphology. Finally, ZnTe was explored in

conjunction with ZnO in order to form type-II band alignment in a core-shell nanostructure.

Various characterization techniques including scanning electron microscopy,

energy-dispersive X-ray spectroscopy , x-ray diffraction, Raman spectroscopy, UV-vis

reflectance spectra and photoluminescence were used to investigate the modification

of ZnO/ZnTe core/shell structure properties. In PL spectra, the eliminated PL intensity

of ZnO wires is primarily attributed to the efficient charge transfer process

occurring between ZnO and ZnTe, due to the band alignment in the core/shell structure. Moreover, the result of UV-vis reflectance spectra corresponds to the band

gap energy of ZnO and ZnTe, respectively, which confirm that the sample consists of

ZnO/ZnTe core/shell structure of good quality.

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Date Created
2017