Single layer of silicon quantum dots in silicon oxide matrix: Investigation of forming gas hydrogenation on photoluminescence properties and study of the composition of silicon rich oxide layers

• Published in: Journal of crystal growth 2011-07, Vol.327 (1), p.84-88
• Main Authors: Aliberti, P., Shrestha, S.K., Li, Ruoyu, Green, M.A., Conibeer, G.J.
• Format: Article
• Language: English
• Subjects: A1. Defects; A1. Nanostructures; A1. Nucleation; Applied sciences; B2. Semiconducting silicon; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Energy; Exact sciences and technology; Forming; Magnetron sputtering; Materials science; Nanoscale materials and structures: fabrication and characterization; Natural energy; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Other topics in nanoscale materials and structures; Oxides; Photoluminescence; Photovoltaic conversion; Physics; Quantum confinement; Quantum dots; Silicon; Silicon dioxide; Solar cells. Photoelectrochemical cells; Solar energy
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2011.05.016

Structures consisting of a single layer of silicon quantum dots in a SiO 2 matrix show interesting optoelectronic properties and potential use as energy selective filters, which are a crucial component for the realization of the hot carrier solar cell. In this work single layer silicon quantum dots in SiO 2 have been realized using a magnetron sputtering technique. Quantum dots are formed by annealing of a silicon rich oxide layer deposited between a thermally grown SiO 2 layer and a sputtered SiO 2 layer. The effects of a forming gas post-hydrogenation process on the photoluminescence of the single layer of quantum dots have been investigated in order to understand the photoluminescence mechanism. It was found that for sputtered silicon quantum dots in SiO 2 matrix the photoemission mechanisms are primarily due to quantum confinement and does not strongly rely on matrix defects. In addition, physical and optical properties of several thick silicon rich oxide layers, with different chemical compositions, have been investigated in order to optimize the stoichiometry of silicon rich oxide in the single layers. ► Photoluminescence mechanism in sputtered single layers of silicon quantum dots in SiO 2 matrix structures is mostly related to quantum confinement. ► Defects at silicon–SiO 2 interface have an active role in the photoluminescence process, but only in creating non-radiative recombination centers and not in generating any additional radiative path for confined excitons. ►Silicon/oxygen atomic ratio of around 1:1 allows for controlling the average size of the silicon quantum dots between two SiO 2 barriers by controlling the thickness of the silicon rich oxide layers.