Browsing by Author "Ghane, Parvin"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Breast Cancer Detection via Microwave Imaging
    (Office of the Vice Chancellor for Research, 2011-04-08) Reid, Joshua R.N.; Ghane, Parvin; Shrestha, Sudhir; Agarwal, Mangilal; Varahramyan, Kody
    Breast cancer is one of the major common diseases among women and takes about 40,000 lives every year. Early detection of breast cancer greatly increases the chance of survival. The norm for today’s detection of breast cancer consists of mammograms, magnetic resonance imaging (MRI), and ultrasonic examination. Unfortunately, the process is a fraction of completeness despite its feeling of discomfort, high cost, and exposure to ionizing radiation which poses cumulative side effects respectively. The present research investigates the efficiency and implementation of microwave imaging to be used in the detection of breast cancer. Microwave imaging (MWI) is a process that illuminates the breast with microwave signals, and receives and analyses scattered signals for breast cancer detection and imaging. The electromagnetic waves that are scattered within the breast provide information that are transmitted and received via microstrip patch antennas, providing an image of detected lesions. In the presented poster, design of a patch antenna and simulation results are presented. In the event of designing, the overall goal was to obtain a voltage standing wave ratio (VSWR) less than 2 at 2.4 GHz signal frequency. To receive the intended results, the dimensions and design of the microstrip patch were important factors given the substrate parameters. Currently, the project is in the prototyping stage for the validation of simulation results and further optimization and development of the antenna for microwave breast cancer detection and imaging applications.
  • Thumbnail Image
    Item
    Fabrication and analysis of CIGS nanoparticle-based thin film solar cells
    (2013-11-20) Ghane, Parvin; Varahramyan, Kody; Agarwal, Mangilal; Rizkalla, Maher E.; King, Brian
    Fabrication and analysis of Copper Indium Gallium di-Selenide (CIGS) nanoparticles-based thin film solar cells are presented and discussed. This work explores non-traditional fabrication processes, such as spray-coating for the low-cost and highly-scalable production of CIGS-based solar cells. CIGS nanoparticles were synthesized and analyzed, thin CIGS films were spray-deposited using nanoparticle inks, and resulting films were used in low-cost fabrication of a set of CIGS solar cell devices. This synthesis method utilizes a chemical colloidal process resulting in the formation of nanoparticles with tunable band gap and size. Based on theoretical and experimental studies, 100 nm nanoparticles with an associated band gap of 1.33 eV were selected to achieve the desired film characteristics and device performances. Scanning electron microcopy (SEM) and size measurement instruments (Zetasizer) were used to study the size and shape of the nanoparticles. Electron dispersive spectroscopy (EDS) results confirmed the presence of the four elements, Copper (Cu), Indium (In), Gallium (Ga), and Selenium (Se) in the synthesized nanoparticles, while X-ray diffraction (XRD) results confirmed the tetragonal chalcopyrite crystal structure. The ultraviolet-visible-near infra-red (UV-Vis-NIR) spectrophotometry results of the nanoparticles depicted light absorbance characteristics with good overlap against the solar irradiance spectrum. The depositions of the nanoparticles were performed using spray-coating techniques. Nanoparticle ink dispersed in ethanol was sprayed using a simple airbrush tool. The thicknesses of the deposited films were controlled through variations in the deposition steps, substrate to spray-nozzle distance, size of the nozzle, and air pressure. Surface features and topology of the spray-deposited films were analyzed using atomic force microscopy (AFM). The deposited films were observed to be relatively uniform with a minimum thickness of 400 nm. Post-annealing of the films at various temperatures was studied for the photoelectric performance of the deposited films. Current density and voltage (J/V) characteristics were measured under light illumination after annealing at different temperatures. It was observed that the highest photoelectric effect resulted in annealing temperatures of 150-250 degree centigrade under air atmosphere. The developed CIGS films were implemented in solar cell devices that included Cadmium Sulfide (CdS) and Zinc Oxide (ZnO) layers. The CdS film served as the n-type layer to form a pn junction with the p-type CIGS layer. In a typical device, a 300 nm CdS layer was deposited through chemical bath deposition on a 1 $mu$m thick CIGS film. A thin layer of intrinsic ZnO was spray coated on the CdS film to prevent shorting with the top conductor layer, 1.5 μm spray-deposited aluminum doped ZnO layer. A set of fabricated devices were tested using a Keithley semiconductor characterization instrument and micromanipulator probe station. The highest measured device efficiency was 1.49%. The considered solar cell devices were simulated in ADEPT 2.0 solar cell simulator based on the given fabrication and experimental parameters. The simulation module developed was successfully calibrated with the experimental results. This module can be used for future development of the given work.
  • Thumbnail Image
    Item
    FABRICATION OF A THIN FILM SOLAR CELLS USING LAYER BY LAYER (LBL) NANOASSEMBLY OF COPPER INDIUM GALLUIM SELENIUM (CIGS) NANOPARTICLES
    (Office of the Vice Chancellor for Research, 2012-04-13) Ghane, Parvin; Hemati, Azadeh; Shrestha, Sudhir; Agarwal, Mangilal; Varahramyan, Kody
    Copper Indium Gallium Selenium (CIGS), a p-type semiconductor material with a tunable band gap, has been broadly studied for high efficiency solar cells as a viable sustainable energy source. Production of CIGS nanoparticles gives the ability of fabricating thin, light, and flexible solar cells. However, the current fabrication technologies of such devices are still very costly. This poster presents the synthesis and functionalization of CIGS nanoparticles and proposes Layer-by-Layer (LbL) nanoassembly process, as a low cost method, to fabricate thin films for solar cell applications. The results show that the synthesized CIGS particles have 1.3 ev band gap and 30 nm diameter in av-erage. These particles were later coated with polymers to provide alternative opposite surface charges suitable for LbL process. Deposition of 20 layers of the particles on indium tinoxide (ITO) coated glass formed a thin film with 220 nm thickness. The measured current voltage (I-V) characteristic of the film gave resistivity of 7.9 MΩ.m in dark and 2.25 MΩ.m under light illumina-tion. A prototype solar cell made out of the film resulted in short circuit cur-rent density (JSC) of 0.3 mA/cm2 and open circuit voltage (VOC) of 0.7 V.