Raman Spectroscopy and Modeling and Simulation of Piezoelectric Quantum Dots

The optical and electronic properties of quantum dots (Q-dots) vary with their size, shape, and composition. A variety of Q-dots have been studied, including ZnO, ZnS, CdSe and perovskites. We have used both Raman spectroscopy (to precisely determine their vibrational frequencies) and UV-VIS spectroscopy (to accurately determine their band gap energies). The electronic band structure and density of states of the ZnO and ZnS Q-dots have been studied under strain using Density Functional Theory (DFT). The computer program SIESTA (Spanish Initiative for Electronic Simulations with Thousands of Atoms) was used to perform the DFT calculations by means of the Linear Combination of Atomic Orbitals (LCAO) method. Semiconducting quantum dots with strain-tunable electronic properties are prime candidates for quantum computing devices, as they have been shown to allow for high degrees of photon entanglement. The spin polarization of such systems may itself be used to encode information or affect the electronic properties of semiconducting quantum dots, which are of particular interest, as they have potential applications in photovoltaic cells, lasers, and imaging.