Subcategory: Materials Science
Marvin Pelzer Jr. - Norfolk State University
Co-Author(s): Dr. Messaoud Bahoura and Donovan Thomas
The effects that metal doping have on the optical and electronic properties of Bulk Quantum Dots (QDs) for eventual device implementation have been briefly studied. Optoelectronic changes in fluorescence intensity/shifting and absorption, by way of Photoluminescence (PL) and UV-VIS respectively, are of interest. Leakage current, capacitance and frequency dispersion data has been examined to observe the electronic behavior of QD’s. X-Ray photoelectron spectroscopy (XPS) and Energy-dispersive X-ray spectroscopy (EDX) characterization confirm the elemental composition of each device, including all materials used. QD thin films were created by drop-casting and film thickness is obtained by X-Ray Reflectivity (XRR). Transmission Electron Microscopy (TEM) will confirm film thickness and individual QD size on a more accurate level. Surface property effects due to doping will be examined using Atomic Force Microscopy (AFM). Preliminary results show that doping Cadmium Selenide (CdSe) QD?s with Gold (III) Acetate does indeed have effects on fluorescence shifting and absorbance. An increase in Gold (III) Acetate concentration causes an increase in red-shifting for PL data. A quick study was done to observe the effects that each concentration of doped CdSe had on MOSCAP structures. Gathered data showed a slight decrease in leakage current as you increase the concentration of Gold (III) Acetate, compared to using HfO2 or undoped CdSe on GaAs solely. This data also indicates that the CdSe:Au layer is more insulating than both GaAs by itself and HfO2 on GaAs. Rare Earth Metals, which are known to have high electrical conductivity and great fluorescence, have also briefly been studied. Doping with Europium (III) Acetate Hydrate has been tested and PL shifting is once again present. A Europium presence at approximately 618 nm was observed. This suggests that there is possible electronic application tunability which is dependent on the metal dopant that is used. Further studies using a combination of various quantum dot systems, metal dopants and semiconductor materials will be conducted to determine the effects that each combination have on optical and electronic properties. Eventual Solar Cell integration and characterization will be done as well.finnal abstract.docx
Funder Acknowledgement(s): NSF-CREST Grant number HRD 1547771 ; NSF-CREST Grant number HRD 1036494
Faculty Advisor: Dr Messaoud Bahoura, email@example.com
Role: I helped with the microwave synthesis and cleaning of the quantum dots. Once the dots were completely separated, i also assisted with the measurements of the fluorescence, electrical properties and the dot's wavelength.