Growth and characterization of semiconductor quantum dots

• Grant number: 19/11742-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2020
• End date: December 31, 2020
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Euclydes Marega Junior
• Grantee: Matheus Fernandes Sousa Lemes
• Host Institution: Instituto de Física de São Carlos (IFSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Associated research grant: 13/07276-1 - CEPOF - Optics and Photonic Research Center, AP.CEPID

Abstract

The main objective of the present project is the growth and the characterization of InAs/GaAs semiconductor quantum dots using molecular beams epitaxy (MBE). At an early stage, the student will participate in quantum dot growth by following all steps of the process from the substrate preparation, subsequent preparation processes before growth and finally the growth of quantum dots samples. Quantum dot samples will be grown on 2-inch GaAs substrates. By keeping the substrate fixed during growth it is possible to obtain regions in the sample with different concentrations of quantum dots. Samples with and without the GaAs cap layer will be fabricated. In the uncovered samples, the density mapping will be done using atomic force microscopy (AFM). In the samples with GaAs coverage, the low temperature micro-luminescence technique will be used. It is possible to identify regions with unique classes (well-defined sizes) of quantum dots on the substrate. In these regions, a mask will be fabricated using optical lithography with reference marks that will be used as a reference to determine, with 10-micrometer precision, regions where it is possible to identify quantum dots of a well defined size through the micro-photoluminescence. In a second step (after the first year of the scholarship), the mapped samples will be used to make plasmonic cavities to study the interaction of surface plasmon-polaritons with individual quantum dots. In a total of 18 months of scholarship, until graduation, the student will have enough material to start a graduate program.