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" Thermally Grown Ga2O3 Thin Films and Nanowires and Their Device Applications "
Mao, Howard
Islam, Saif
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Latin Dissertation
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| Language of Document
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English
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| Record Number
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1052296
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| Doc. No
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TL51413
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| Main Entry
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Mao, Howard
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| Title & Author
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Thermally Grown Ga2O3 Thin Films and Nanowires and Their Device Applications\ Mao, HowardIslam, Saif
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| College
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University of California, Davis
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| Date
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2019
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| Degree
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M.S.
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| student score
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2019
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| Note
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39 p.
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| Abstract
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In recent years, interest in wide bandgap materials such as diamond, SiC and GaN has grown due to their ability to withstand operation in high temperature and high-power environments as well as their ability to absorb light in the ultraviolet spectrum while not showing a significant response for light outside of that spectrum. Ga2O3 is a wide bandgap semiconductor (4.9 eV) that shows promise in applications such as UV photodetection and power electronics. It has been used in a variety of applications, including UV photodetectors, gas sensors, field emitters, and MOS capacitors. With a wider bandgap and higher breakdown voltage than both GaN (3.2 eV) and SiC (2.4 eV), it can handle even higher temperatures and voltages than those two materials. As such, much research has focused on fabricating devices with this material. UV photodetectors have become more important in recent years for applications such as communications, ozone hole monitoring, and missile and flame detection. Their main figure of merit is their spectral selectivity, meaning how effective they are at detecting light of a certain wavelength while not being affected by light of other wavelengths. Ga2O3 has proven to be an attractive material for making UV photodetectors, with different types such as the basic photoconductor as well as a variety of photodiodes such as Schottky, MSM, p-n, p-i-n, and avalanche photodiodes all having been fabricated using Ga2O3. Its wide bandgap makes it sensitive to UV light and blind to other wavelengths of light. Usage of high-k materials in power devices can allow them to handle operation at high voltages, and this is another area where Ga2O3 has great potential. Ga2O3 has been used as both a dielectric material and a substrate for transistors and capacitors to produce devices with high breakdown voltages. The Baliga and Johnson figures of merit, which quantify a material’s suitability for power electronics at high frequencies, are also higher for Ga2O3 than they are for GaN and SiC, which means that theoretically a Ga2O3 device should be able to handle higher voltages than devices made with the other two materials. This speaks to just how useful Ga2O3 can be for high-power applications. One of the barriers for more widespread use of Ga2O3 in devices is its cost. In this thesis, we explore possible inexpensive methods to generate thin films and nanostructures of Ga2O3, demonstrating two inexpensive methods for growing two-dimensional (2D) Ga2O3 thin films. One of them involves oxidizing GaAs wafers in a horizontal tube furnace and the other is a sol-gel method-based film deposition process. As a third method, we also applied liquid Ga films onto quartz substrates at room temperature and oxidized them at high temperature to grow one-dimensional (1D) Ga2O3 nanowires. The thin films grown using thermal oxidation and the sol gel method were used to fabricate UV photodetectors and MOS capacitors, respectively while the nanowires were characterized under UV illumination. Material and electrical characterization were performed on all of the samples after growth and device fabrication. The results showed that thermal oxidation and the sol-gel method can be used to grow Ga2O3 inexpensively for applications in devices and sensors.
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| Descriptor
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Alternative energy
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Applied physics
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Electrical engineering
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Materials science
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Mechanics
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Nanotechnology
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| Added Entry
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Islam, Saif
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| Added Entry
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University of California, Davis
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