Quantum dots for intermediate-band GaAs solar cells

• Grant number: 24/23311-6
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: May 01, 2025
• End date: February 28, 2029
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Alain André Quivy
• Grantee: Lucas Andrade Teixeira de Souza
• Host Institution: Instituto de Física (IF). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

In this project, the student will continue and expand the research started during his master's degree with a scholarship from FAPESP. The main objective is to demonstrate the possibility of surpassing the conversion efficiency of a conventional single-junction solar cell, by inserting in the middle of the p-i-n junction some type of quantum dot that will be optimized during the project. Thus, we hope to be able to efficiently absorb solar radiation whose energy is lower than that of the gap of the host matrix, energy that is normally wasted. We will start with InAs/GaAs submonolayer quantum dots (SMLQDs) deposited at low temperature, in order to reduce the segregation of In atoms, as this phenomenon is considerably harming the performance of SMLQDs. Another method will be to use InAlAs/GaAs SMLQDs, since it was recently observed that the presence of Al atoms can limit the consequences of segregation in the epitaxial layers. Finally, we will use quantum dots obtained by the droplet epitaxy technique, which makes it possible to obtain nanostructures from various materials, with independent control of their density and size, and without the need for the presence of elastic tension, as in the case of the Stranski-Krastanov growth mode. (AU)